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| author | Serhiy Storchaka <storchaka@gmail.com> | 2016-06-09 16:03:23 +0300 |
|---|---|---|
| committer | Serhiy Storchaka <storchaka@gmail.com> | 2016-06-09 16:03:23 +0300 |
| commit | 6426ccd1891ad4b69b60ef185d8fdfee1e63ba0a (patch) | |
| tree | e9cab63af0c51148e88dcb92638976b6e00eaefb /Doc | |
| parent | 7b8126c1c27b49a88e7ed1a40df39e51a4e87b40 (diff) | |
| parent | 756c4a7107e1a3ef7afc95fe3a55b04105cbb172 (diff) | |
| download | cpython-6426ccd1891ad4b69b60ef185d8fdfee1e63ba0a.tar.gz | |
Issue #26305: Argument Clinic now escapes braces. No need to double them.
Diffstat (limited to 'Doc')
89 files changed, 2151 insertions, 378 deletions
diff --git a/Doc/Makefile b/Doc/Makefile index a42e98bd9c..03a37f1e49 100644 --- a/Doc/Makefile +++ b/Doc/Makefile @@ -153,7 +153,7 @@ dist: cp -pPR build/epub/Python.epub dist/python-$(DISTVERSION)-docs.epub check: - $(PYTHON) tools/rstlint.py -i tools + $(PYTHON) tools/rstlint.py -i tools -i venv serve: ../Tools/scripts/serve.py build/html diff --git a/Doc/c-api/arg.rst b/Doc/c-api/arg.rst index 983d113f0a..d9f0f43e62 100644 --- a/Doc/c-api/arg.rst +++ b/Doc/c-api/arg.rst @@ -206,8 +206,7 @@ Unless otherwise stated, buffers are not NUL-terminated. :c:func:`PyArg_ParseTuple` will use this location as the buffer and interpret the initial value of *\*buffer_length* as the buffer size. It will then copy the encoded data into the buffer and NUL-terminate it. If the buffer is not large - enough, a :exc:`TypeError` will be set. - Note: starting from Python 3.6 a :exc:`ValueError` will be set. + enough, a :exc:`ValueError` will be set. In both cases, *\*buffer_length* is set to the length of the encoded data without the trailing NUL byte. diff --git a/Doc/c-api/exceptions.rst b/Doc/c-api/exceptions.rst index 19cbb3bcb8..226b61972f 100644 --- a/Doc/c-api/exceptions.rst +++ b/Doc/c-api/exceptions.rst @@ -334,6 +334,14 @@ an error value). .. versionadded:: 3.2 +.. c:function:: int PyErr_ResourceWarning(PyObject *source, Py_ssize_t stack_level, const char *format, ...) + + Function similar to :c:func:`PyErr_WarnFormat`, but *category* is + :exc:`ResourceWarning` and pass *source* to :func:`warnings.WarningMessage`. + + .. versionadded:: 3.6 + + Querying the error indicator ============================ diff --git a/Doc/c-api/init.rst b/Doc/c-api/init.rst index 639819ce29..d77836a34a 100644 --- a/Doc/c-api/init.rst +++ b/Doc/c-api/init.rst @@ -25,7 +25,7 @@ Initializing and finalizing the interpreter triple: module; search; path single: PySys_SetArgv() single: PySys_SetArgvEx() - single: Py_Finalize() + single: Py_FinalizeEx() Initialize the Python interpreter. In an application embedding Python, this should be called before using any other Python/C API functions; with the @@ -34,7 +34,7 @@ Initializing and finalizing the interpreter modules :mod:`builtins`, :mod:`__main__` and :mod:`sys`. It also initializes the module search path (``sys.path``). It does not set ``sys.argv``; use :c:func:`PySys_SetArgvEx` for that. This is a no-op when called for a second time - (without calling :c:func:`Py_Finalize` first). There is no return value; it is a + (without calling :c:func:`Py_FinalizeEx` first). There is no return value; it is a fatal error if the initialization fails. @@ -48,19 +48,20 @@ Initializing and finalizing the interpreter .. c:function:: int Py_IsInitialized() Return true (nonzero) when the Python interpreter has been initialized, false - (zero) if not. After :c:func:`Py_Finalize` is called, this returns false until + (zero) if not. After :c:func:`Py_FinalizeEx` is called, this returns false until :c:func:`Py_Initialize` is called again. -.. c:function:: void Py_Finalize() +.. c:function:: int Py_FinalizeEx() Undo all initializations made by :c:func:`Py_Initialize` and subsequent use of Python/C API functions, and destroy all sub-interpreters (see :c:func:`Py_NewInterpreter` below) that were created and not yet destroyed since the last call to :c:func:`Py_Initialize`. Ideally, this frees all memory allocated by the Python interpreter. This is a no-op when called for a second - time (without calling :c:func:`Py_Initialize` again first). There is no return - value; errors during finalization are ignored. + time (without calling :c:func:`Py_Initialize` again first). Normally the + return value is 0. If there were errors during finalization + (flushing buffered data), -1 is returned. This function is provided for a number of reasons. An embedding application might want to restart Python without having to restart the application itself. @@ -79,7 +80,15 @@ Initializing and finalizing the interpreter freed. Some memory allocated by extension modules may not be freed. Some extensions may not work properly if their initialization routine is called more than once; this can happen if an application calls :c:func:`Py_Initialize` and - :c:func:`Py_Finalize` more than once. + :c:func:`Py_FinalizeEx` more than once. + + .. versionadded:: 3.6 + + +.. c:function:: void Py_Finalize() + + This is a backwards-compatible version of :c:func:`Py_FinalizeEx` that + disregards the return value. Process-wide parameters @@ -107,7 +116,7 @@ Process-wide parameters Note that :data:`sys.stderr` always uses the "backslashreplace" error handler, regardless of this (or any other) setting. - If :c:func:`Py_Finalize` is called, this function will need to be called + If :c:func:`Py_FinalizeEx` is called, this function will need to be called again in order to affect subsequent calls to :c:func:`Py_Initialize`. Returns 0 if successful, a nonzero value on error (e.g. calling after the @@ -918,7 +927,7 @@ using the following functions: entry.) .. index:: - single: Py_Finalize() + single: Py_FinalizeEx() single: Py_Initialize() Extension modules are shared between (sub-)interpreters as follows: the first @@ -928,7 +937,7 @@ using the following functions: and filled with the contents of this copy; the extension's ``init`` function is not called. Note that this is different from what happens when an extension is imported after the interpreter has been completely re-initialized by calling - :c:func:`Py_Finalize` and :c:func:`Py_Initialize`; in that case, the extension's + :c:func:`Py_FinalizeEx` and :c:func:`Py_Initialize`; in that case, the extension's ``initmodule`` function *is* called again. .. index:: single: close() (in module os) @@ -936,14 +945,14 @@ using the following functions: .. c:function:: void Py_EndInterpreter(PyThreadState *tstate) - .. index:: single: Py_Finalize() + .. index:: single: Py_FinalizeEx() Destroy the (sub-)interpreter represented by the given thread state. The given thread state must be the current thread state. See the discussion of thread states below. When the call returns, the current thread state is *NULL*. All thread states associated with this interpreter are destroyed. (The global interpreter lock must be held before calling this function and is still held - when it returns.) :c:func:`Py_Finalize` will destroy all sub-interpreters that + when it returns.) :c:func:`Py_FinalizeEx` will destroy all sub-interpreters that haven't been explicitly destroyed at that point. diff --git a/Doc/c-api/intro.rst b/Doc/c-api/intro.rst index bc3a752132..74681d2c85 100644 --- a/Doc/c-api/intro.rst +++ b/Doc/c-api/intro.rst @@ -64,9 +64,10 @@ The header files are typically installed with Python. On Unix, these are located in the directories :file:`{prefix}/include/pythonversion/` and :file:`{exec_prefix}/include/pythonversion/`, where :envvar:`prefix` and :envvar:`exec_prefix` are defined by the corresponding parameters to Python's -:program:`configure` script and *version* is ``sys.version[:3]``. On Windows, -the headers are installed in :file:`{prefix}/include`, where :envvar:`prefix` is -the installation directory specified to the installer. +:program:`configure` script and *version* is +``'%d.%d' % sys.version_info[:2]``. On Windows, the headers are installed +in :file:`{prefix}/include`, where :envvar:`prefix` is the installation +directory specified to the installer. To include the headers, place both directories (if different) on your compiler's search path for includes. Do *not* place the parent directories on the search @@ -578,9 +579,9 @@ Sometimes, it is desirable to "uninitialize" Python. For instance, the application may want to start over (make another call to :c:func:`Py_Initialize`) or the application is simply done with its use of Python and wants to free memory allocated by Python. This can be accomplished -by calling :c:func:`Py_Finalize`. The function :c:func:`Py_IsInitialized` returns +by calling :c:func:`Py_FinalizeEx`. The function :c:func:`Py_IsInitialized` returns true if Python is currently in the initialized state. More information about -these functions is given in a later chapter. Notice that :c:func:`Py_Finalize` +these functions is given in a later chapter. Notice that :c:func:`Py_FinalizeEx` does *not* free all memory allocated by the Python interpreter, e.g. memory allocated by extension modules currently cannot be released. diff --git a/Doc/c-api/memory.rst b/Doc/c-api/memory.rst index 290ef09dce..3ff545275f 100644 --- a/Doc/c-api/memory.rst +++ b/Doc/c-api/memory.rst @@ -85,9 +85,12 @@ for the I/O buffer escapes completely the Python memory manager. .. seealso:: + The :envvar:`PYTHONMALLOC` environment variable can be used to configure + the memory allocators used by Python. + The :envvar:`PYTHONMALLOCSTATS` environment variable can be used to print - memory allocation statistics every time a new object arena is created, and - on shutdown. + statistics of the :ref:`pymalloc memory allocator <pymalloc>` every time a + new pymalloc object arena is created, and on shutdown. Raw Memory Interface @@ -162,15 +165,17 @@ The following function sets, modeled after the ANSI C standard, but specifying behavior when requesting zero bytes, are available for allocating and releasing memory from the Python heap. -The default memory block allocator uses the following functions: -:c:func:`malloc`, :c:func:`calloc`, :c:func:`realloc` and :c:func:`free`; call -``malloc(1)`` (or ``calloc(1, 1)``) when requesting zero bytes. +By default, these functions use :ref:`pymalloc memory allocator <pymalloc>`. .. warning:: The :term:`GIL <global interpreter lock>` must be held when using these functions. +.. versionchanged:: 3.6 + + The default allocator is now pymalloc instead of system :c:func:`malloc`. + .. c:function:: void* PyMem_Malloc(size_t n) Allocates *n* bytes and returns a pointer of type :c:type:`void\*` to the @@ -292,15 +297,32 @@ Customize Memory Allocators Enum used to identify an allocator domain. Domains: - * :c:data:`PYMEM_DOMAIN_RAW`: functions :c:func:`PyMem_RawMalloc`, - :c:func:`PyMem_RawRealloc`, :c:func:`PyMem_RawCalloc` and - :c:func:`PyMem_RawFree` - * :c:data:`PYMEM_DOMAIN_MEM`: functions :c:func:`PyMem_Malloc`, - :c:func:`PyMem_Realloc`, :c:func:`PyMem_Calloc` and :c:func:`PyMem_Free` - * :c:data:`PYMEM_DOMAIN_OBJ`: functions :c:func:`PyObject_Malloc`, - :c:func:`PyObject_Realloc`, :c:func:`PyObject_Calloc` and - :c:func:`PyObject_Free` + .. c:var:: PYMEM_DOMAIN_RAW + + Functions: + + * :c:func:`PyMem_RawMalloc` + * :c:func:`PyMem_RawRealloc` + * :c:func:`PyMem_RawCalloc` + * :c:func:`PyMem_RawFree` + + .. c:var:: PYMEM_DOMAIN_MEM + + Functions: + + * :c:func:`PyMem_Malloc`, + * :c:func:`PyMem_Realloc` + * :c:func:`PyMem_Calloc` + * :c:func:`PyMem_Free` + .. c:var:: PYMEM_DOMAIN_OBJ + + Functions: + + * :c:func:`PyObject_Malloc` + * :c:func:`PyObject_Realloc` + * :c:func:`PyObject_Calloc` + * :c:func:`PyObject_Free` .. c:function:: void PyMem_GetAllocator(PyMemAllocatorDomain domain, PyMemAllocatorEx *allocator) @@ -325,43 +347,62 @@ Customize Memory Allocators .. c:function:: void PyMem_SetupDebugHooks(void) - Setup hooks to detect bugs in the following Python memory allocator - functions: - - - :c:func:`PyMem_RawMalloc`, :c:func:`PyMem_RawRealloc`, - :c:func:`PyMem_RawCalloc`, :c:func:`PyMem_RawFree` - - :c:func:`PyMem_Malloc`, :c:func:`PyMem_Realloc`, :c:func:`PyMem_Calloc`, - :c:func:`PyMem_Free` - - :c:func:`PyObject_Malloc`, :c:func:`PyObject_Realloc`, - :c:func:`PyObject_Calloc`, :c:func:`PyObject_Free` + Setup hooks to detect bugs in the Python memory allocator functions. Newly allocated memory is filled with the byte ``0xCB``, freed memory is - filled with the byte ``0xDB``. Additional checks: + filled with the byte ``0xDB``. - - detect API violations, ex: :c:func:`PyObject_Free` called on a buffer + Runtime checks: + + - Detect API violations, ex: :c:func:`PyObject_Free` called on a buffer allocated by :c:func:`PyMem_Malloc` - - detect write before the start of the buffer (buffer underflow) - - detect write after the end of the buffer (buffer overflow) + - Detect write before the start of the buffer (buffer underflow) + - Detect write after the end of the buffer (buffer overflow) + - Check that the :term:`GIL <global interpreter lock>` is held when + allocator functions of :c:data:`PYMEM_DOMAIN_OBJ` (ex: + :c:func:`PyObject_Malloc`) and :c:data:`PYMEM_DOMAIN_MEM` (ex: + :c:func:`PyMem_Malloc`) domains are called + + On error, the debug hooks use the :mod:`tracemalloc` module to get the + traceback where a memory block was allocated. The traceback is only + displayed if :mod:`tracemalloc` is tracing Python memory allocations and the + memory block was traced. - The function does nothing if Python is not compiled is debug mode. + These hooks are installed by default if Python is compiled in debug + mode. The :envvar:`PYTHONMALLOC` environment variable can be used to install + debug hooks on a Python compiled in release mode. + .. versionchanged:: 3.6 + This function now also works on Python compiled in release mode. + On error, the debug hooks now use :mod:`tracemalloc` to get the traceback + where a memory block was allocated. The debug hooks now also check + if the GIL is held when functions of :c:data:`PYMEM_DOMAIN_OBJ` and + :c:data:`PYMEM_DOMAIN_MEM` domains are called. -Customize PyObject Arena Allocator -================================== -Python has a *pymalloc* allocator for allocations smaller than 512 bytes. This -allocator is optimized for small objects with a short lifetime. It uses memory -mappings called "arenas" with a fixed size of 256 KB. It falls back to -:c:func:`PyMem_RawMalloc` and :c:func:`PyMem_RawRealloc` for allocations larger -than 512 bytes. *pymalloc* is the default allocator used by -:c:func:`PyObject_Malloc`. +.. _pymalloc: -The default arena allocator uses the following functions: +The pymalloc allocator +====================== + +Python has a *pymalloc* allocator optimized for small objects (smaller or equal +to 512 bytes) with a short lifetime. It uses memory mappings called "arenas" +with a fixed size of 256 KB. It falls back to :c:func:`PyMem_RawMalloc` and +:c:func:`PyMem_RawRealloc` for allocations larger than 512 bytes. + +*pymalloc* is the default allocator of the :c:data:`PYMEM_DOMAIN_MEM` (ex: +:c:func:`PyObject_Malloc`) and :c:data:`PYMEM_DOMAIN_OBJ` (ex: +:c:func:`PyObject_Malloc`) domains. + +The arena allocator uses the following functions: * :c:func:`VirtualAlloc` and :c:func:`VirtualFree` on Windows, * :c:func:`mmap` and :c:func:`munmap` if available, * :c:func:`malloc` and :c:func:`free` otherwise. +Customize pymalloc Arena Allocator +---------------------------------- + .. versionadded:: 3.4 .. c:type:: PyObjectArenaAllocator diff --git a/Doc/c-api/sys.rst b/Doc/c-api/sys.rst index 3d83b279c2..9ba6496247 100644 --- a/Doc/c-api/sys.rst +++ b/Doc/c-api/sys.rst @@ -212,20 +212,24 @@ Process Control .. c:function:: void Py_Exit(int status) .. index:: - single: Py_Finalize() + single: Py_FinalizeEx() single: exit() - Exit the current process. This calls :c:func:`Py_Finalize` and then calls the - standard C library function ``exit(status)``. + Exit the current process. This calls :c:func:`Py_FinalizeEx` and then calls the + standard C library function ``exit(status)``. If :c:func:`Py_FinalizeEx` + indicates an error, the exit status is set to 120. + + .. versionchanged:: 3.6 + Errors from finalization no longer ignored. .. c:function:: int Py_AtExit(void (*func) ()) .. index:: - single: Py_Finalize() + single: Py_FinalizeEx() single: cleanup functions - Register a cleanup function to be called by :c:func:`Py_Finalize`. The cleanup + Register a cleanup function to be called by :c:func:`Py_FinalizeEx`. The cleanup function will be called with no arguments and should return no value. At most 32 cleanup functions can be registered. When the registration is successful, :c:func:`Py_AtExit` returns ``0``; on failure, it returns ``-1``. The cleanup diff --git a/Doc/extending/embedding.rst b/Doc/extending/embedding.rst index acd60aef8c..1546b1adcf 100644 --- a/Doc/extending/embedding.rst +++ b/Doc/extending/embedding.rst @@ -67,7 +67,9 @@ perform some operation on a file. :: Py_Initialize(); PyRun_SimpleString("from time import time,ctime\n" "print('Today is', ctime(time()))\n"); - Py_Finalize(); + if (Py_FinalizeEx() < 0) { + exit(120); + } PyMem_RawFree(program); return 0; } @@ -76,7 +78,7 @@ The :c:func:`Py_SetProgramName` function should be called before :c:func:`Py_Initialize` to inform the interpreter about paths to Python run-time libraries. Next, the Python interpreter is initialized with :c:func:`Py_Initialize`, followed by the execution of a hard-coded Python script -that prints the date and time. Afterwards, the :c:func:`Py_Finalize` call shuts +that prints the date and time. Afterwards, the :c:func:`Py_FinalizeEx` call shuts the interpreter down, followed by the end of the program. In a real program, you may want to get the Python script from another source, perhaps a text-editor routine, a file, or a database. Getting the Python code from a file can better diff --git a/Doc/faq/programming.rst b/Doc/faq/programming.rst index 694753e5b9..9c5e20dcad 100644 --- a/Doc/faq/programming.rst +++ b/Doc/faq/programming.rst @@ -838,7 +838,8 @@ How do I convert a number to a string? To convert, e.g., the number 144 to the string '144', use the built-in type constructor :func:`str`. If you want a hexadecimal or octal representation, use the built-in functions :func:`hex` or :func:`oct`. For fancy formatting, see -the :ref:`formatstrings` section, e.g. ``"{:04d}".format(144)`` yields +the :ref:`f-strings` and :ref:`formatstrings` sections, +e.g. ``"{:04d}".format(144)`` yields ``'0144'`` and ``"{:.3f}".format(1.0/3.0)`` yields ``'0.333'``. diff --git a/Doc/howto/argparse.rst b/Doc/howto/argparse.rst index cfe9868875..7a60165f42 100644 --- a/Doc/howto/argparse.rst +++ b/Doc/howto/argparse.rst @@ -547,7 +547,8 @@ And this is what it gives: Traceback (most recent call last): File "prog.py", line 11, in <module> if args.verbosity >= 2: - TypeError: unorderable types: NoneType() >= int() + TypeError: '>=' not supported between instances of 'NoneType' and 'int' + * First output went well, and fixes the bug we had before. That is, we want any value >= 2 to be as verbose as possible. diff --git a/Doc/includes/run-func.c b/Doc/includes/run-func.c index 986d670319..ead7bdd232 100644 --- a/Doc/includes/run-func.c +++ b/Doc/includes/run-func.c @@ -63,6 +63,8 @@ main(int argc, char *argv[]) fprintf(stderr, "Failed to load \"%s\"\n", argv[1]); return 1; } - Py_Finalize(); + if (Py_FinalizeEx() < 0) { + return 120; + } return 0; } diff --git a/Doc/includes/test.py b/Doc/includes/test.py index 7ebf46afd1..9e9d4a6712 100644 --- a/Doc/includes/test.py +++ b/Doc/includes/test.py @@ -204,7 +204,7 @@ Test cyclic gc(?) import os import sys from distutils.util import get_platform -PLAT_SPEC = "%s-%s" % (get_platform(), sys.version[0:3]) +PLAT_SPEC = "%s-%d.%d" % (get_platform(), *sys.version_info[:2]) src = os.path.join("build", "lib.%s" % PLAT_SPEC) sys.path.append(src) diff --git a/Doc/library/asynchat.rst b/Doc/library/asynchat.rst index 56ad4f8f3f..1ff3dd8a3d 100644 --- a/Doc/library/asynchat.rst +++ b/Doc/library/asynchat.rst @@ -57,13 +57,13 @@ connection requests. The asynchronous output buffer size (default ``4096``). Unlike :class:`asyncore.dispatcher`, :class:`async_chat` allows you to - define a first-in-first-out queue (fifo) of *producers*. A producer need + define a :abbr:`FIFO (first-in, first-out)` queue of *producers*. A producer need have only one method, :meth:`more`, which should return data to be transmitted on the channel. The producer indicates exhaustion (*i.e.* that it contains no more data) by having its :meth:`more` method return the empty bytes object. At this point - the :class:`async_chat` object removes the producer from the fifo and starts - using the next producer, if any. When the producer fifo is empty the + the :class:`async_chat` object removes the producer from the queue and starts + using the next producer, if any. When the producer queue is empty the :meth:`handle_write` method does nothing. You use the channel object's :meth:`set_terminator` method to describe how to recognize the end of, or an important breakpoint in, an incoming transmission from the remote @@ -77,8 +77,8 @@ connection requests. .. method:: async_chat.close_when_done() - Pushes a ``None`` on to the producer fifo. When this producer is popped off - the fifo it causes the channel to be closed. + Pushes a ``None`` on to the producer queue. When this producer is popped off + the queue it causes the channel to be closed. .. method:: async_chat.collect_incoming_data(data) @@ -91,7 +91,7 @@ connection requests. .. method:: async_chat.discard_buffers() In emergencies this method will discard any data held in the input and/or - output buffers and the producer fifo. + output buffers and the producer queue. .. method:: async_chat.found_terminator() @@ -109,7 +109,7 @@ connection requests. .. method:: async_chat.push(data) - Pushes data on to the channel's fifo to ensure its transmission. + Pushes data on to the channel's queue to ensure its transmission. This is all you need to do to have the channel write the data out to the network, although it is possible to use your own producers in more complex schemes to implement encryption and chunking, for example. @@ -117,7 +117,7 @@ connection requests. .. method:: async_chat.push_with_producer(producer) - Takes a producer object and adds it to the producer fifo associated with + Takes a producer object and adds it to the producer queue associated with the channel. When all currently-pushed producers have been exhausted the channel will consume this producer's data by calling its :meth:`more` method and send the data to the remote endpoint. diff --git a/Doc/library/asyncio-eventloop.rst b/Doc/library/asyncio-eventloop.rst index 7ec3aa106e..809a3e77d5 100644 --- a/Doc/library/asyncio-eventloop.rst +++ b/Doc/library/asyncio-eventloop.rst @@ -101,8 +101,9 @@ keywords to your callback, use :func:`functools.partial`. For example, called after :meth:`call_soon` returns, when control returns to the event loop. - This operates as a FIFO queue, callbacks are called in the order in - which they are registered. Each callback will be called exactly once. + This operates as a :abbr:`FIFO (first-in, first-out)` queue, callbacks + are called in the order in which they are registered. Each callback + will be called exactly once. Any positional arguments after the callback will be passed to the callback when it is called. diff --git a/Doc/library/binascii.rst b/Doc/library/binascii.rst index 1752c63929..f92f6dfd64 100644 --- a/Doc/library/binascii.rst +++ b/Doc/library/binascii.rst @@ -52,13 +52,14 @@ The :mod:`binascii` module defines the following functions: than one line may be passed at a time. -.. function:: b2a_base64(data) +.. function:: b2a_base64(data, \*, newline=True) Convert binary data to a line of ASCII characters in base64 coding. The return - value is the converted line, including a newline char. The newline is - added because the original use case for this function was to feed it a - series of 57 byte input lines to get output lines that conform to the - MIME-base64 standard. Otherwise the output conforms to :rfc:`3548`. + value is the converted line, including a newline char if *newline* is + true. The output of this function conforms to :rfc:`3548`. + + .. versionchanged:: 3.6 + Added the *newline* parameter. .. function:: a2b_qp(data, header=False) diff --git a/Doc/library/collections.abc.rst b/Doc/library/collections.abc.rst index e76ca78340..ec10a1e5ce 100644 --- a/Doc/library/collections.abc.rst +++ b/Doc/library/collections.abc.rst @@ -40,12 +40,13 @@ ABC Inherits from Abstract Methods Mixin :class:`Hashable` ``__hash__`` :class:`Iterable` ``__iter__`` :class:`Iterator` :class:`Iterable` ``__next__`` ``__iter__`` +:class:`Reversible` :class:`Iterable` ``__reversed__`` :class:`Generator` :class:`Iterator` ``send``, ``throw`` ``close``, ``__iter__``, ``__next__`` :class:`Sized` ``__len__`` :class:`Callable` ``__call__`` :class:`Sequence` :class:`Sized`, ``__getitem__``, ``__contains__``, ``__iter__``, ``__reversed__``, - :class:`Iterable`, ``__len__`` ``index``, and ``count`` + :class:`Reversible`, ``__len__`` ``index``, and ``count`` :class:`Container` :class:`MutableSequence` :class:`Sequence` ``__getitem__``, Inherited :class:`Sequence` methods and @@ -107,6 +108,12 @@ ABC Inherits from Abstract Methods Mixin :meth:`~iterator.__next__` methods. See also the definition of :term:`iterator`. +.. class:: Reversible + + ABC for classes that provide the :meth:`__reversed__` method. + + .. versionadded:: 3.6 + .. class:: Generator ABC for generator classes that implement the protocol defined in diff --git a/Doc/library/collections.rst b/Doc/library/collections.rst index b8f0621d1a..619e488372 100644 --- a/Doc/library/collections.rst +++ b/Doc/library/collections.rst @@ -963,6 +963,9 @@ customize a prototype instance: constructor that is convenient for use cases where named tuples are being subclassed. + * :meth:`types.SimpleNamespace` for a mutable namespace based on an underlying + dictionary instead of a tuple. + :class:`OrderedDict` objects ---------------------------- @@ -984,8 +987,9 @@ the items are returned in the order their keys were first added. .. method:: popitem(last=True) The :meth:`popitem` method for ordered dictionaries returns and removes a - (key, value) pair. The pairs are returned in LIFO order if *last* is true - or FIFO order if false. + (key, value) pair. The pairs are returned in + :abbr:`LIFO (last-in, first-out)` order if *last* is true + or :abbr:`FIFO (first-in, first-out)` order if false. .. method:: move_to_end(key, last=True) diff --git a/Doc/library/compileall.rst b/Doc/library/compileall.rst index c5736f2043..679c2b4858 100644 --- a/Doc/library/compileall.rst +++ b/Doc/library/compileall.rst @@ -103,7 +103,8 @@ Public functions .. function:: compile_dir(dir, maxlevels=10, ddir=None, force=False, rx=None, quiet=0, legacy=False, optimize=-1, workers=1) Recursively descend the directory tree named by *dir*, compiling all :file:`.py` - files along the way. + files along the way. Return a true value if all the files compiled successfully, + and a false value otherwise. The *maxlevels* parameter is used to limit the depth of the recursion; it defaults to ``10``. @@ -155,7 +156,8 @@ Public functions .. function:: compile_file(fullname, ddir=None, force=False, rx=None, quiet=0, legacy=False, optimize=-1) - Compile the file with path *fullname*. + Compile the file with path *fullname*. Return a true value if the file + compiled successfully, and a false value otherwise. If *ddir* is given, it is prepended to the path to the file being compiled for use in compilation time tracebacks, and is also compiled in to the @@ -191,8 +193,10 @@ Public functions .. function:: compile_path(skip_curdir=True, maxlevels=0, force=False, quiet=0, legacy=False, optimize=-1) - Byte-compile all the :file:`.py` files found along ``sys.path``. If - *skip_curdir* is true (the default), the current directory is not included + Byte-compile all the :file:`.py` files found along ``sys.path``. Return a + true value if all the files compiled successfully, and a false value otherwise. + + If *skip_curdir* is true (the default), the current directory is not included in the search. All other parameters are passed to the :func:`compile_dir` function. Note that unlike the other compile functions, ``maxlevels`` defaults to ``0``. diff --git a/Doc/library/contextlib.rst b/Doc/library/contextlib.rst index cf85fcd4b2..11de8b169c 100644 --- a/Doc/library/contextlib.rst +++ b/Doc/library/contextlib.rst @@ -18,6 +18,18 @@ Utilities Functions and classes provided: +.. class:: AbstractContextManager + + An abstract base class for classes that implement + :meth:`object.__enter__` and :meth:`object.__exit__`. A default + implementation for :meth:`object.__enter__` is provided which returns + ``self`` while :meth:`object.__exit__` is an abstract method which by default + returns ``None``. See also the definition of :ref:`typecontextmanager`. + + .. versionadded:: 3.6 + + + .. decorator:: contextmanager This function is a :term:`decorator` that can be used to define a factory @@ -447,9 +459,9 @@ Here's an example of doing this for a context manager that accepts resource acquisition and release functions, along with an optional validation function, and maps them to the context management protocol:: - from contextlib import contextmanager, ExitStack + from contextlib import contextmanager, AbstractContextManager, ExitStack - class ResourceManager: + class ResourceManager(AbstractContextManager): def __init__(self, acquire_resource, release_resource, check_resource_ok=None): self.acquire_resource = acquire_resource diff --git a/Doc/library/crypt.rst b/Doc/library/crypt.rst index 0661426f71..42ae32e649 100644 --- a/Doc/library/crypt.rst +++ b/Doc/library/crypt.rst @@ -64,7 +64,7 @@ Module Attributes A list of available password hashing algorithms, as ``crypt.METHOD_*`` objects. This list is sorted from strongest to - weakest, and is guaranteed to have at least ``crypt.METHOD_CRYPT``. + weakest. Module Functions diff --git a/Doc/library/crypto.rst b/Doc/library/crypto.rst index 1eddfdc12c..ae45549a6d 100644 --- a/Doc/library/crypto.rst +++ b/Doc/library/crypto.rst @@ -16,3 +16,4 @@ Here's an overview: hashlib.rst hmac.rst + secrets.rst diff --git a/Doc/library/datetime.rst b/Doc/library/datetime.rst index 3c6081902d..4b6b46780c 100644 --- a/Doc/library/datetime.rst +++ b/Doc/library/datetime.rst @@ -607,7 +607,8 @@ Instance methods: .. method:: date.__format__(format) Same as :meth:`.date.strftime`. This makes it possible to specify a format - string for a :class:`.date` object when using :meth:`str.format`. For a + string for a :class:`.date` object in :ref:`formatted string + literals <f-strings>` and when using :meth:`str.format`. For a complete list of formatting directives, see :ref:`strftime-strptime-behavior`. @@ -1135,7 +1136,7 @@ Instance methods: ``self.date().isocalendar()``. -.. method:: datetime.isoformat(sep='T') +.. method:: datetime.isoformat(sep='T', timespec='auto') Return a string representing the date and time in ISO 8601 format, YYYY-MM-DDTHH:MM:SS.mmmmmm or, if :attr:`microsecond` is 0, @@ -1156,6 +1157,37 @@ Instance methods: >>> datetime(2002, 12, 25, tzinfo=TZ()).isoformat(' ') '2002-12-25 00:00:00-06:39' + The optional argument *timespec* specifies the number of additional + components of the time to include (the default is ``'auto'``). + It can be one of the following: + + - ``'auto'``: Same as ``'seconds'`` if :attr:`microsecond` is 0, + same as ``'microseconds'`` otherwise. + - ``'hours'``: Include the :attr:`hour` in the two-digit HH format. + - ``'minutes'``: Include :attr:`hour` and :attr:`minute` in HH:MM format. + - ``'seconds'``: Include :attr:`hour`, :attr:`minute`, and :attr:`second` + in HH:MM:SS format. + - ``'milliseconds'``: Include full time, but truncate fractional second + part to milliseconds. HH:MM:SS.sss format. + - ``'microseconds'``: Include full time in HH:MM:SS.mmmmmm format. + + .. note:: + + Excluded time components are truncated, not rounded. + + :exc:`ValueError` will be raised on an invalid *timespec* argument. + + + >>> from datetime import datetime + >>> datetime.now().isoformat(timespec='minutes') + '2002-12-25T00:00' + >>> dt = datetime(2015, 1, 1, 12, 30, 59, 0) + >>> dt.isoformat(timespec='microseconds') + '2015-01-01T12:30:59.000000' + + .. versionadded:: 3.6 + Added the *timespec* argument. + .. method:: datetime.__str__() @@ -1182,7 +1214,8 @@ Instance methods: .. method:: datetime.__format__(format) Same as :meth:`.datetime.strftime`. This makes it possible to specify a format - string for a :class:`.datetime` object when using :meth:`str.format`. For a + string for a :class:`.datetime` object in :ref:`formatted string + literals <f-strings>` and when using :meth:`str.format`. For a complete list of formatting directives, see :ref:`strftime-strptime-behavior`. @@ -1404,13 +1437,46 @@ Instance methods: aware :class:`.time`, without conversion of the time data. -.. method:: time.isoformat() +.. method:: time.isoformat(timespec='auto') Return a string representing the time in ISO 8601 format, HH:MM:SS.mmmmmm or, if - self.microsecond is 0, HH:MM:SS If :meth:`utcoffset` does not return ``None``, a + :attr:`microsecond` is 0, HH:MM:SS If :meth:`utcoffset` does not return ``None``, a 6-character string is appended, giving the UTC offset in (signed) hours and minutes: HH:MM:SS.mmmmmm+HH:MM or, if self.microsecond is 0, HH:MM:SS+HH:MM + The optional argument *timespec* specifies the number of additional + components of the time to include (the default is ``'auto'``). + It can be one of the following: + + - ``'auto'``: Same as ``'seconds'`` if :attr:`microsecond` is 0, + same as ``'microseconds'`` otherwise. + - ``'hours'``: Include the :attr:`hour` in the two-digit HH format. + - ``'minutes'``: Include :attr:`hour` and :attr:`minute` in HH:MM format. + - ``'seconds'``: Include :attr:`hour`, :attr:`minute`, and :attr:`second` + in HH:MM:SS format. + - ``'milliseconds'``: Include full time, but truncate fractional second + part to milliseconds. HH:MM:SS.sss format. + - ``'microseconds'``: Include full time in HH:MM:SS.mmmmmm format. + + .. note:: + + Excluded time components are truncated, not rounded. + + :exc:`ValueError` will be raised on an invalid *timespec* argument. + + + >>> from datetime import time + >>> time(hour=12, minute=34, second=56, microsecond=123456).isoformat(timespec='minutes') + '12:34' + >>> dt = time(hour=12, minute=34, second=56, microsecond=0) + >>> dt.isoformat(timespec='microseconds') + '12:34:56.000000' + >>> dt.isoformat(timespec='auto') + '12:34:56' + + .. versionadded:: 3.6 + Added the *timespec* argument. + .. method:: time.__str__() @@ -1427,7 +1493,8 @@ Instance methods: .. method:: time.__format__(format) Same as :meth:`.time.strftime`. This makes it possible to specify a format string - for a :class:`.time` object when using :meth:`str.format`. For a + for a :class:`.time` object in :ref:`formatted string + literals <f-strings>` and when using :meth:`str.format`. For a complete list of formatting directives, see :ref:`strftime-strptime-behavior`. @@ -1738,10 +1805,7 @@ made to civil time. otherwise :exc:`ValueError` is raised. The *name* argument is optional. If specified it must be a string that - is used as the value returned by the ``tzname(dt)`` method. Otherwise, - ``tzname(dt)`` returns a string 'UTCsHH:MM', where s is the sign of - *offset*, HH and MM are two digits of ``offset.hours`` and - ``offset.minutes`` respectively. + will be used as the value returned by the :meth:`datetime.tzname` method. .. versionadded:: 3.2 @@ -1754,11 +1818,19 @@ made to civil time. .. method:: timezone.tzname(dt) - Return the fixed value specified when the :class:`timezone` instance is - constructed or a string 'UTCsHH:MM', where s is the sign of - *offset*, HH and MM are two digits of ``offset.hours`` and + Return the fixed value specified when the :class:`timezone` instance + is constructed. If *name* is not provided in the constructor, the + name returned by ``tzname(dt)`` is generated from the value of the + ``offset`` as follows. If *offset* is ``timedelta(0)``, the name + is "UTC", otherwise it is a string 'UTC±HH:MM', where ± is the sign + of ``offset``, HH and MM are two digits of ``offset.hours`` and ``offset.minutes`` respectively. + .. versionchanged:: 3.6 + Name generated from ``offset=timedelta(0)`` is now plain 'UTC', not + 'UTC+00:00'. + + .. method:: timezone.dst(dt) Always returns ``None``. @@ -1908,6 +1980,34 @@ format codes. | ``%%`` | A literal ``'%'`` character. | % | | +-----------+--------------------------------+------------------------+-------+ +Several additional directives not required by the C89 standard are included for +convenience. These parameters all correspond to ISO 8601 date values. These +may not be available on all platforms when used with the :meth:`strftime` +method. The ISO 8601 year and ISO 8601 week directives are not interchangeable +with the year and week number directives above. Calling :meth:`strptime` with +incomplete or ambiguous ISO 8601 directives will raise a :exc:`ValueError`. + ++-----------+--------------------------------+------------------------+-------+ +| Directive | Meaning | Example | Notes | ++===========+================================+========================+=======+ +| ``%G`` | ISO 8601 year with century | 0001, 0002, ..., 2013, | \(8) | +| | representing the year that | 2014, ..., 9998, 9999 | | +| | contains the greater part of | | | +| | the ISO week (``%V``). | | | ++-----------+--------------------------------+------------------------+-------+ +| ``%u`` | ISO 8601 weekday as a decimal | 1, 2, ..., 7 | | +| | number where 1 is Monday. | | | ++-----------+--------------------------------+------------------------+-------+ +| ``%V`` | ISO 8601 week as a decimal | 01, 02, ..., 53 | \(8) | +| | number with Monday as | | | +| | the first day of the week. | | | +| | Week 01 is the week containing | | | +| | Jan 4. | | | ++-----------+--------------------------------+------------------------+-------+ + +.. versionadded:: 3.6 + ``%G``, ``%u`` and ``%V`` were added. + Notes: (1) @@ -1972,7 +2072,14 @@ Notes: (7) When used with the :meth:`strptime` method, ``%U`` and ``%W`` are only used - in calculations when the day of the week and the year are specified. + in calculations when the day of the week and the calendar year (``%Y``) + are specified. + +(8) + Similar to ``%U`` and ``%W``, ``%V`` is only used in calculations when the + day of the week and the ISO year (``%G``) are specified in a + :meth:`strptime` format string. Also note that ``%G`` and ``%Y`` are not + interchangeable. .. rubric:: Footnotes diff --git a/Doc/library/decimal.rst b/Doc/library/decimal.rst index d46f850fd7..6796f8adba 100644 --- a/Doc/library/decimal.rst +++ b/Doc/library/decimal.rst @@ -445,6 +445,19 @@ Decimal objects ``Decimal('321e+5').adjusted()`` returns seven. Used for determining the position of the most significant digit with respect to the decimal point. + .. method:: as_integer_ratio() + + Return a pair ``(n, d)`` of integers that represent the given + :class:`Decimal` instance as a fraction, in lowest terms and + with a positive denominator:: + + >>> Decimal('-3.14').as_integer_ratio() + (-157, 50) + + The conversion is exact. Raise OverflowError on infinities and ValueError + on NaNs. + + .. versionadded:: 3.6 .. method:: as_tuple() diff --git a/Doc/library/dis.rst b/Doc/library/dis.rst index d2d8ac7839..6e4b8b106f 100644 --- a/Doc/library/dis.rst +++ b/Doc/library/dis.rst @@ -31,9 +31,9 @@ the following command can be used to display the disassembly of >>> dis.dis(myfunc) 2 0 LOAD_GLOBAL 0 (len) - 3 LOAD_FAST 0 (alist) - 6 CALL_FUNCTION 1 - 9 RETURN_VALUE + 2 LOAD_FAST 0 (alist) + 4 CALL_FUNCTION 1 + 6 RETURN_VALUE (The "2" is a line number). @@ -682,8 +682,7 @@ iterations of the loop. .. XXX explain the WHY stuff! -All of the following opcodes expect arguments. An argument is two bytes, with -the more significant byte last. +All of the following opcodes use their arguments. .. opcode:: STORE_NAME (namei) @@ -989,6 +988,28 @@ the more significant byte last. arguments. +.. opcode:: FORMAT_VALUE (flags) + + Used for implementing formatted literal strings (f-strings). Pops + an optional *fmt_spec* from the stack, then a required *value*. + *flags* is interpreted as follows: + + * ``(flags & 0x03) == 0x00``: *value* is formatted as-is. + * ``(flags & 0x03) == 0x01``: call :func:`str` on *value* before + formatting it. + * ``(flags & 0x03) == 0x02``: call :func:`repr` on *value* before + formatting it. + * ``(flags & 0x03) == 0x03``: call :func:`ascii` on *value* before + formatting it. + * ``(flags & 0x04) == 0x04``: pop *fmt_spec* from the stack and use + it, else use an empty *fmt_spec*. + + Formatting is performed using :c:func:`PyObject_Format`. The + result is pushed on the stack. + + .. versionadded:: 3.6 + + .. opcode:: HAVE_ARGUMENT This is not really an opcode. It identifies the dividing line between diff --git a/Doc/library/enum.rst b/Doc/library/enum.rst index 60467b4acb..99a7f8e923 100644 --- a/Doc/library/enum.rst +++ b/Doc/library/enum.rst @@ -558,7 +558,8 @@ Some rules: 4. %-style formatting: `%s` and `%r` call the :class:`Enum` class's :meth:`__str__` and :meth:`__repr__` respectively; other codes (such as `%i` or `%h` for IntEnum) treat the enum member as its mixed-in type. -5. :meth:`str.format` (or :func:`format`) will use the mixed-in +5. :ref:`Formatted string literals <f-strings>`, :meth:`str.format`, + and :func:`format` will use the mixed-in type's :meth:`__format__`. If the :class:`Enum` class's :func:`str` or :func:`repr` is desired, use the `!s` or `!r` format codes. @@ -747,6 +748,15 @@ besides the :class:`Enum` member you looking for:: .. versionchanged:: 3.5 +Boolean evaluation: Enum classes that are mixed with non-Enum types (such as +:class:`int`, :class:`str`, etc.) are evaluated according to the mixed-in +type's rules; otherwise, all members evaluate as ``True``. To make your own +Enum's boolean evaluation depend on the member's value add the following to +your class:: + + def __bool__(self): + return bool(self.value) + The :attr:`__members__` attribute is only available on the class. If you give your :class:`Enum` subclass extra methods, like the `Planet`_ diff --git a/Doc/library/faulthandler.rst b/Doc/library/faulthandler.rst index 3a5badd0ff..3c49649c74 100644 --- a/Doc/library/faulthandler.rst +++ b/Doc/library/faulthandler.rst @@ -68,6 +68,9 @@ Fault handler state .. versionchanged:: 3.5 Added support for passing file descriptor to this function. + .. versionchanged:: 3.6 + On Windows, a handler for Windows exception is also installed. + .. function:: disable() Disable the fault handler: uninstall the signal handlers installed by diff --git a/Doc/library/fileinput.rst b/Doc/library/fileinput.rst index a55bbe324f..8efe8e3b94 100644 --- a/Doc/library/fileinput.rst +++ b/Doc/library/fileinput.rst @@ -71,9 +71,8 @@ The following function is the primary interface of this module: .. versionchanged:: 3.2 Can be used as a context manager. - .. versionchanged:: 3.5.2 - The *bufsize* parameter is no longer used. - + .. deprecated-removed:: 3.6 3.8 + The *bufsize* parameter. The following functions use the global state created by :func:`fileinput.input`; if there is no active state, :exc:`RuntimeError` is raised. @@ -166,8 +165,8 @@ available for subclassing as well: .. deprecated:: 3.4 The ``'rU'`` and ``'U'`` modes. - .. versionchanged:: 3.5.2 - The *bufsize* parameter is no longer used. + .. deprecated-removed:: 3.6 3.8 + The *bufsize* parameter. **Optional in-place filtering:** if the keyword argument ``inplace=True`` is @@ -194,10 +193,14 @@ The two following opening hooks are provided by this module: Usage example: ``fi = fileinput.FileInput(openhook=fileinput.hook_compressed)`` -.. function:: hook_encoded(encoding) +.. function:: hook_encoded(encoding, errors=None) Returns a hook which opens each file with :func:`open`, using the given - *encoding* to read the file. + *encoding* and *errors* to read the file. Usage example: ``fi = - fileinput.FileInput(openhook=fileinput.hook_encoded("iso-8859-1"))`` + fileinput.FileInput(openhook=fileinput.hook_encoded("utf-8", + "surrogateescape"))`` + + .. versionchanged:: 3.6 + Added the optional *errors* parameter. diff --git a/Doc/library/functions.rst b/Doc/library/functions.rst index c3563f3690..6f7ba1fe8a 100644 --- a/Doc/library/functions.rst +++ b/Doc/library/functions.rst @@ -878,11 +878,11 @@ are always available. They are listed here in alphabetical order. Open *file* and return a corresponding :term:`file object`. If the file cannot be opened, an :exc:`OSError` is raised. - *file* is either a string or bytes object giving the pathname (absolute or - relative to the current working directory) of the file to be opened or - an integer file descriptor of the file to be wrapped. (If a file descriptor - is given, it is closed when the returned I/O object is closed, unless - *closefd* is set to ``False``.) + *file* is either a string, bytes, or :class:`os.PathLike` object giving the + pathname (absolute or relative to the current working directory) of the file + to be opened or an integer file descriptor of the file to be wrapped. (If a + file descriptor is given, it is closed when the returned I/O object is + closed, unless *closefd* is set to ``False``.) *mode* is an optional string that specifies the mode in which the file is opened. It defaults to ``'r'`` which means open for reading in text mode. diff --git a/Doc/library/grp.rst b/Doc/library/grp.rst index 88821406a3..c840cfe67a 100644 --- a/Doc/library/grp.rst +++ b/Doc/library/grp.rst @@ -42,6 +42,9 @@ It defines the following items: Return the group database entry for the given numeric group ID. :exc:`KeyError` is raised if the entry asked for cannot be found. + .. deprecated:: 3.6 + Since Python 3.6 the support of non-integer arguments like floats or + strings in :func:`getgrgid` is deprecated. .. function:: getgrnam(name) diff --git a/Doc/library/http.server.rst b/Doc/library/http.server.rst index 05ad2d7bab..8f2ba89545 100644 --- a/Doc/library/http.server.rst +++ b/Doc/library/http.server.rst @@ -370,10 +370,9 @@ the current directory:: Handler = http.server.SimpleHTTPRequestHandler - httpd = socketserver.TCPServer(("", PORT), Handler) - - print("serving at port", PORT) - httpd.serve_forever() + with socketserver.TCPServer(("", PORT), Handler) as httpd: + print("serving at port", PORT) + httpd.serve_forever() .. _http-server-cli: diff --git a/Doc/library/imaplib.rst b/Doc/library/imaplib.rst index dbd8e7747f..e33bac0778 100644 --- a/Doc/library/imaplib.rst +++ b/Doc/library/imaplib.rst @@ -500,6 +500,17 @@ An :class:`IMAP4` instance has the following methods: M.store(num, '+FLAGS', '\\Deleted') M.expunge() + .. note:: + + Creating flags containing ']' (for example: "[test]") violates + :rfc:`3501` (the IMAP protocol). However, imaplib has historically + allowed creation of such tags, and popular IMAP servers, such as Gmail, + accept and produce such flags. There are non-Python programs which also + create such tags. Although it is an RFC violation and IMAP clients and + servers are supposed to be strict, imaplib nonetheless continues to allow + such tags to be created for backward compatibility reasons, and as of + python 3.6, handles them if they are sent from the server, since this + improves real-world compatibility. .. method:: IMAP4.subscribe(mailbox) diff --git a/Doc/library/imp.rst b/Doc/library/imp.rst index 68a6b681ef..420031ab48 100644 --- a/Doc/library/imp.rst +++ b/Doc/library/imp.rst @@ -81,7 +81,9 @@ This module provides an interface to the mechanisms used to implement the .. deprecated:: 3.3 Use :func:`importlib.util.find_spec` instead unless Python 3.3 compatibility is required, in which case use - :func:`importlib.find_loader`. + :func:`importlib.find_loader`. For example usage of the former case, + see the :ref:`importlib-examples` section of the :mod:`importlib` + documentation. .. function:: load_module(name, file, pathname, description) @@ -108,9 +110,12 @@ This module provides an interface to the mechanisms used to implement the If previously used in conjunction with :func:`imp.find_module` then consider using :func:`importlib.import_module`, otherwise use the loader returned by the replacement you chose for :func:`imp.find_module`. If you - called :func:`imp.load_module` and related functions directly then use the - classes in :mod:`importlib.machinery`, e.g. - ``importlib.machinery.SourceFileLoader(name, path).load_module()``. + called :func:`imp.load_module` and related functions directly with file + path arguments then use a combination of + :func:`importlib.util.spec_from_file_location` and + :func:`importlib.util.module_from_spec`. See the :ref:`importlib-examples` + section of the :mod:`importlib` documentation for details of the various + approaches. .. function:: new_module(name) @@ -119,7 +124,7 @@ This module provides an interface to the mechanisms used to implement the in ``sys.modules``. .. deprecated:: 3.4 - Use :class:`types.ModuleType` instead. + Use :func:`importlib.util.module_from_spec` instead. .. function:: reload(module) diff --git a/Doc/library/importlib.rst b/Doc/library/importlib.rst index 953e21b3a3..3eb2e8a201 100644 --- a/Doc/library/importlib.rst +++ b/Doc/library/importlib.rst @@ -259,7 +259,7 @@ ABC hierarchy:: module and *path* will be the value of :attr:`__path__` from the parent package. If a spec cannot be found, ``None`` is returned. When passed in, ``target`` is a module object that the finder may - use to make a more educated about what spec to return. + use to make a more educated guess about what spec to return. .. versionadded:: 3.4 @@ -309,7 +309,7 @@ ABC hierarchy:: within the :term:`path entry` to which it is assigned. If a spec cannot be found, ``None`` is returned. When passed in, ``target`` is a module object that the finder may use to make a more educated - about what spec to return. + guess about what spec to return. .. versionadded:: 3.4 @@ -924,6 +924,10 @@ find and load modules. Concrete implementation of :meth:`importlib.abc.Loader.load_module` where specifying the name of the module to load is optional. + .. deprecated:: 3.6 + + Use :meth:`importlib.abc.Loader.exec_module` instead. + .. class:: SourcelessFileLoader(fullname, path) @@ -963,6 +967,10 @@ find and load modules. Concrete implementation of :meth:`importlib.abc.Loader.load_module` where specifying the name of the module to load is optional. + .. deprecated:: 3.6 + + Use :meth:`importlib.abc.Loader.exec_module` instead. + .. class:: ExtensionFileLoader(fullname, path) @@ -1303,3 +1311,120 @@ an :term:`importer`. loader = importlib.machinery.SourceFileLoader lazy_loader = importlib.util.LazyLoader.factory(loader) finder = importlib.machinery.FileFinder(path, (lazy_loader, suffixes)) + +.. _importlib-examples: + +Examples +-------- + +To programmatically import a module, use :func:`importlib.import_module`. +:: + + import importlib + + itertools = importlib.import_module('itertools') + +If you need to find out if a module can be imported without actually doing the +import, then you should use :func:`importlib.util.find_spec`. +:: + + import importlib.util + import sys + + # For illustrative purposes. + name = 'itertools' + + spec = importlib.util.find_spec(name) + if spec is None: + print("can't find the itertools module") + else: + # If you chose to perform the actual import ... + module = importlib.util.module_from_spec(spec) + spec.loader.exec_module(module) + # Adding the module to sys.modules is optional. + sys.modules[name] = module + +To import a Python source file directly, use the following recipe +(Python 3.4 and newer only):: + + import importlib.util + import sys + + # For illustrative purposes. + import tokenize + file_path = tokenize.__file__ + module_name = tokenize.__name__ + + spec = importlib.util.spec_from_file_location(module_name, file_path) + module = importlib.util.module_from_spec(spec) + spec.loader.exec_module(module) + # Optional; only necessary if you want to be able to import the module + # by name later. + sys.modules[module_name] = module + +For deep customizations of import, you typically want to implement an +:term:`importer`. This means managing both the :term:`finder` and :term:`loader` +side of things. For finders there are two flavours to choose from depending on +your needs: a :term:`meta path finder` or a :term:`path entry finder`. The +former is what you would put on :attr:`sys.meta_path` while the latter is what +you create using a :term:`path entry hook` on :attr:`sys.path_hooks` which works +with :attr:`sys.path` entries to potentially create a finder. This example will +show you how to register your own importers so that import will use them (for +creating an importer for yourself, read the documentation for the appropriate +classes defined within this package):: + + import importlib.machinery + import sys + + # For illustrative purposes only. + SpamMetaPathFinder = importlib.machinery.PathFinder + SpamPathEntryFinder = importlib.machinery.FileFinder + loader_details = (importlib.machinery.SourceFileLoader, + importlib.machinery.SOURCE_SUFFIXES) + + # Setting up a meta path finder. + # Make sure to put the finder in the proper location in the list in terms of + # priority. + sys.meta_path.append(SpamMetaPathFinder) + + # Setting up a path entry finder. + # Make sure to put the path hook in the proper location in the list in terms + # of priority. + sys.path_hooks.append(SpamPathEntryFinder.path_hook(loader_details)) + +Import itself is implemented in Python code, making it possible to +expose most of the import machinery through importlib. The following +helps illustrate the various APIs that importlib exposes by providing an +approximate implementation of +:func:`importlib.import_module` (Python 3.4 and newer for the importlib usage, +Python 3.6 and newer for other parts of the code). +:: + + import importlib.util + import sys + + def import_module(name, package=None): + """An approximate implementation of import.""" + absolute_name = importlib.util.resolve_name(name, package) + try: + return sys.modules[absolute_name] + except KeyError: + pass + + path = None + if '.' in absolute_name: + parent_name, _, child_name = absolute_name.rpartition('.') + parent_module = import_module(parent_name) + path = parent_module.spec.submodule_search_locations + for finder in sys.meta_path: + spec = finder.find_spec(absolute_name, path) + if spec is not None: + break + else: + raise ImportError(f'No module named {absolute_name!r}') + module = importlib.util.module_from_spec(spec) + spec.loader.exec_module(module) + sys.modules[absolute_name] = module + if path is not None: + setattr(parent_module, child_name, module) + return module diff --git a/Doc/library/inspect.rst b/Doc/library/inspect.rst index ff628de1bd..3b3637967e 100644 --- a/Doc/library/inspect.rst +++ b/Doc/library/inspect.rst @@ -234,24 +234,6 @@ attributes: listed in the metaclass' custom :meth:`__dir__`. -.. function:: getmoduleinfo(path) - - Returns a :term:`named tuple` ``ModuleInfo(name, suffix, mode, module_type)`` - of values that describe how Python will interpret the file identified by - *path* if it is a module, or ``None`` if it would not be identified as a - module. In that tuple, *name* is the name of the module without the name of - any enclosing package, *suffix* is the trailing part of the file name (which - may not be a dot-delimited extension), *mode* is the :func:`open` mode that - would be used (``'r'`` or ``'rb'``), and *module_type* is an integer giving - the type of the module. *module_type* will have a value which can be - compared to the constants defined in the :mod:`imp` module; see the - documentation for that module for more information on module types. - - .. deprecated:: 3.3 - You may check the file path's suffix against the supported suffixes - listed in :mod:`importlib.machinery` to infer the same information. - - .. function:: getmodulename(path) Return the name of the module named by the file *path*, without including the @@ -265,8 +247,7 @@ attributes: still return ``None``. .. versionchanged:: 3.3 - This function is now based directly on :mod:`importlib` rather than the - deprecated :func:`getmoduleinfo`. + The function is based directly on :mod:`importlib`. .. function:: ismodule(object) @@ -644,6 +625,16 @@ function. The name of the parameter as a string. The name must be a valid Python identifier. + .. impl-detail:: + + CPython generates implicit parameter names of the form ``.0`` on the + code objects used to implement comprehensions and generator + expressions. + + .. versionchanged:: 3.6 + These parameter names are exposed by this module as names like + ``implicit0``. + .. attribute:: Parameter.default The default value for the parameter. If the parameter has no default @@ -852,8 +843,6 @@ Classes and functions from kwonlyargs to defaults. *annotations* is a dictionary mapping argument names to annotations. - The first four items in the tuple correspond to :func:`getargspec`. - .. versionchanged:: 3.4 This function is now based on :func:`signature`, but still ignores ``__wrapped__`` attributes and includes the already bound first @@ -882,7 +871,7 @@ Classes and functions .. function:: formatargspec(args[, varargs, varkw, defaults, kwonlyargs, kwonlydefaults, annotations[, formatarg, formatvarargs, formatvarkw, formatvalue, formatreturns, formatannotations]]) Format a pretty argument spec from the values returned by - :func:`getargspec` or :func:`getfullargspec`. + :func:`getfullargspec`. The first seven arguments are (``args``, ``varargs``, ``varkw``, ``defaults``, ``kwonlyargs``, ``kwonlydefaults``, ``annotations``). diff --git a/Doc/library/itertools.rst b/Doc/library/itertools.rst index c6e2544d3c..9ff42cc0ce 100644 --- a/Doc/library/itertools.rst +++ b/Doc/library/itertools.rst @@ -590,7 +590,13 @@ loops that truncate the stream. .. function:: tee(iterable, n=2) - Return *n* independent iterators from a single iterable. Roughly equivalent to:: + Return *n* independent iterators from a single iterable. + + The following Python code helps explain what *tee* does (although the actual + implementation is more complex and uses only a single underlying + :abbr:`FIFO (first-in, first-out)` queue). + + Roughly equivalent to:: def tee(iterable, n=2): it = iter(iterable) diff --git a/Doc/library/logging.handlers.rst b/Doc/library/logging.handlers.rst index 5936e12e07..f89d6c346f 100644 --- a/Doc/library/logging.handlers.rst +++ b/Doc/library/logging.handlers.rst @@ -162,11 +162,19 @@ for this value. first call to :meth:`emit`. By default, the file grows indefinitely. + .. method:: reopenIfNeeded() + + Checks to see if the file has changed. If it has, the existing stream is + flushed and closed and the file opened again, typically as a precursor to + outputting the record to the file. + + .. versionadded:: 3.6 + + .. method:: emit(record) - Outputs the record to the file, but first checks to see if the file has - changed. If it has, the existing stream is flushed and closed and the - file opened again, before outputting the record to the file. + Outputs the record to the file, but first calls :meth:`reopenIfNeeded` to + reopen the file if it has changed. .. _base-rotating-handler: diff --git a/Doc/library/mmap.rst b/Doc/library/mmap.rst index ce807e43eb..f26a4d44be 100644 --- a/Doc/library/mmap.rst +++ b/Doc/library/mmap.rst @@ -263,13 +263,18 @@ To map anonymous memory, -1 should be passed as the fileno along with the length .. method:: write(bytes) Write the bytes in *bytes* into memory at the current position of the - file pointer; the file position is updated to point after the bytes that - were written. If the mmap was created with :const:`ACCESS_READ`, then + file pointer and return the number of bytes written (never less than + ``len(bytes)``, since if the write fails, a :exc:`ValueError` will be + raised). The file position is updated to point after the bytes that + were written. If the mmap was created with :const:`ACCESS_READ`, then writing to it will raise a :exc:`TypeError` exception. .. versionchanged:: 3.5 Writable :term:`bytes-like object` is now accepted. + .. versionchanged:: 3.6 + The number of bytes written is now returned. + .. method:: write_byte(byte) diff --git a/Doc/library/multiprocessing.rst b/Doc/library/multiprocessing.rst index be6c28ce0c..fcf4e14b1c 100644 --- a/Doc/library/multiprocessing.rst +++ b/Doc/library/multiprocessing.rst @@ -644,8 +644,9 @@ primitives like locks. For passing messages one can use :func:`Pipe` (for a connection between two processes) or a queue (which allows multiple producers and consumers). -The :class:`Queue`, :class:`SimpleQueue` and :class:`JoinableQueue` types are multi-producer, -multi-consumer FIFO queues modelled on the :class:`queue.Queue` class in the +The :class:`Queue`, :class:`SimpleQueue` and :class:`JoinableQueue` types +are multi-producer, multi-consumer :abbr:`FIFO (first-in, first-out)` +queues modelled on the :class:`queue.Queue` class in the standard library. They differ in that :class:`Queue` lacks the :meth:`~queue.Queue.task_done` and :meth:`~queue.Queue.join` methods introduced into Python 2.5's :class:`queue.Queue` class. @@ -883,8 +884,13 @@ Miscellaneous .. function:: cpu_count() - Return the number of CPUs in the system. May raise - :exc:`NotImplementedError`. + Return the number of CPUs in the system. + + This number is not equivalent to the number of CPUs the current process can + use. The number of usable CPUs can be obtained with + ``len(os.sched_getaffinity(0))`` + + May raise :exc:`NotImplementedError`. .. seealso:: :func:`os.cpu_count` diff --git a/Doc/library/os.rst b/Doc/library/os.rst index 785b080cff..deabaebe72 100644 --- a/Doc/library/os.rst +++ b/Doc/library/os.rst @@ -186,6 +186,15 @@ process and user. .. versionadded:: 3.2 +.. function:: fspath(path) + + Return the string representation of the path. + + If :class:`str` or :class:`bytes` is passed in, it is returned unchanged; + otherwise, the result of calling ``type(path).__fspath__`` is returned, or an + exception is raised. + + .. function:: getenv(key, default=None) Return the value of the environment variable *key* if it exists, or @@ -1891,14 +1900,29 @@ features: :attr:`~DirEntry.path` attributes of each :class:`DirEntry` will be of the same type as *path*. + The :func:`scandir` iterator supports the :term:`context manager` protocol + and has the following method: + + .. method:: scandir.close() + + Close the iterator and free acquired resources. + + This is called automatically when the iterator is exhausted or garbage + collected, or when an error happens during iterating. However it + is advisable to call it explicitly or use the :keyword:`with` + statement. + + .. versionadded:: 3.6 + The following example shows a simple use of :func:`scandir` to display all the files (excluding directories) in the given *path* that don't start with ``'.'``. The ``entry.is_file()`` call will generally not make an additional system call:: - for entry in os.scandir(path): - if not entry.name.startswith('.') and entry.is_file(): - print(entry.name) + with os.scandir(path) as it: + for entry in it: + if not entry.name.startswith('.') and entry.is_file(): + print(entry.name) .. note:: @@ -1914,6 +1938,12 @@ features: .. versionadded:: 3.5 + .. versionadded:: 3.6 + Added support for the :term:`context manager` protocol and the + :func:`~scandir.close()` method. If a :func:`scandir` iterator is neither + exhausted nor explicitly closed a :exc:`ResourceWarning` will be emitted + in its destructor. + .. class:: DirEntry @@ -3606,6 +3636,11 @@ Miscellaneous System Information Return the number of CPUs in the system. Returns None if undetermined. + This number is not equivalent to the number of CPUs the current process can + use. The number of usable CPUs can be obtained with + ``len(os.sched_getaffinity(0))`` + + .. versionadded:: 3.4 diff --git a/Doc/library/pathlib.rst b/Doc/library/pathlib.rst index 2f0654440d..ff5196de86 100644 --- a/Doc/library/pathlib.rst +++ b/Doc/library/pathlib.rst @@ -195,7 +195,7 @@ Paths of a different flavour compare unequal and cannot be ordered:: >>> PureWindowsPath('foo') < PurePosixPath('foo') Traceback (most recent call last): File "<stdin>", line 1, in <module> - TypeError: unorderable types: PureWindowsPath() < PurePosixPath() + TypeError: '<' not supported between instances of 'PureWindowsPath' and 'PurePosixPath' Operators diff --git a/Doc/library/pickle.rst b/Doc/library/pickle.rst index 7e09b03cc6..24192774dd 100644 --- a/Doc/library/pickle.rst +++ b/Doc/library/pickle.rst @@ -488,7 +488,7 @@ methods: .. method:: object.__getnewargs_ex__() - In protocols 4 and newer, classes that implements the + In protocols 2 and newer, classes that implements the :meth:`__getnewargs_ex__` method can dictate the values passed to the :meth:`__new__` method upon unpickling. The method must return a pair ``(args, kwargs)`` where *args* is a tuple of positional arguments @@ -500,15 +500,22 @@ methods: class requires keyword-only arguments. Otherwise, it is recommended for compatibility to implement :meth:`__getnewargs__`. + .. versionchanged:: 3.6 + :meth:`__getnewargs_ex__` is now used in protocols 2 and 3. + .. method:: object.__getnewargs__() - This method serve a similar purpose as :meth:`__getnewargs_ex__` but - for protocols 2 and newer. It must return a tuple of arguments ``args`` - which will be passed to the :meth:`__new__` method upon unpickling. + This method serve a similar purpose as :meth:`__getnewargs_ex__`, but + supports only positional arguments. It must return a tuple of arguments + ``args`` which will be passed to the :meth:`__new__` method upon unpickling. + + :meth:`__getnewargs__` will not be called if :meth:`__getnewargs_ex__` is + defined. - In protocols 4 and newer, :meth:`__getnewargs__` will not be called if - :meth:`__getnewargs_ex__` is defined. + .. versionchanged:: 3.6 + Before Python 3.6, :meth:`__getnewargs__` was called instead of + :meth:`__getnewargs_ex__` in protocols 2 and 3. .. method:: object.__getstate__() diff --git a/Doc/library/queue.rst b/Doc/library/queue.rst index 1cb0935377..e3eaa3f3bf 100644 --- a/Doc/library/queue.rst +++ b/Doc/library/queue.rst @@ -16,8 +16,9 @@ availability of thread support in Python; see the :mod:`threading` module. The module implements three types of queue, which differ only in the order in -which the entries are retrieved. In a FIFO queue, the first tasks added are -the first retrieved. In a LIFO queue, the most recently added entry is +which the entries are retrieved. In a :abbr:`FIFO (first-in, first-out)` +queue, the first tasks added are the first retrieved. In a +:abbr:`LIFO (last-in, first-out)` queue, the most recently added entry is the first retrieved (operating like a stack). With a priority queue, the entries are kept sorted (using the :mod:`heapq` module) and the lowest valued entry is retrieved first. @@ -27,14 +28,16 @@ The :mod:`queue` module defines the following classes and exceptions: .. class:: Queue(maxsize=0) - Constructor for a FIFO queue. *maxsize* is an integer that sets the upperbound + Constructor for a :abbr:`FIFO (first-in, first-out)` queue. *maxsize* is + an integer that sets the upperbound limit on the number of items that can be placed in the queue. Insertion will block once this size has been reached, until queue items are consumed. If *maxsize* is less than or equal to zero, the queue size is infinite. .. class:: LifoQueue(maxsize=0) - Constructor for a LIFO queue. *maxsize* is an integer that sets the upperbound + Constructor for a :abbr:`LIFO (last-in, first-out)` queue. *maxsize* is + an integer that sets the upperbound limit on the number of items that can be placed in the queue. Insertion will block once this size has been reached, until queue items are consumed. If *maxsize* is less than or equal to zero, the queue size is infinite. diff --git a/Doc/library/random.rst b/Doc/library/random.rst index df502a0aff..e7b81adb64 100644 --- a/Doc/library/random.rst +++ b/Doc/library/random.rst @@ -46,7 +46,8 @@ from sources provided by the operating system. .. warning:: The pseudo-random generators of this module should not be used for - security purposes. + security purposes. For security or cryptographic uses, see the + :mod:`secrets` module. Bookkeeping functions: diff --git a/Doc/library/readline.rst b/Doc/library/readline.rst index 42e0ad56a5..f77792030f 100644 --- a/Doc/library/readline.rst +++ b/Doc/library/readline.rst @@ -156,6 +156,20 @@ The following functions operate on a global history list: This calls :c:func:`add_history` in the underlying library. +.. function:: set_auto_history(enabled) + + Enable or disable automatic calls to :c:func:`add_history` when reading + input via readline. The *enabled* argument should be a Boolean value + that when true, enables auto history, and that when False, disables + auto history. + + .. versionadded:: 3.6 + + .. impl-detail:: + Auto history is enabled by default, and changes to this do not persist + across multiple sessions. + + Startup hooks ------------- diff --git a/Doc/library/secrets.rst b/Doc/library/secrets.rst new file mode 100644 index 0000000000..9bf848f911 --- /dev/null +++ b/Doc/library/secrets.rst @@ -0,0 +1,198 @@ +:mod:`secrets` --- Generate secure random numbers for managing secrets +====================================================================== + +.. module:: secrets + :synopsis: Generate secure random numbers for managing secrets. + +.. moduleauthor:: Steven D'Aprano <steve+python@pearwood.info> +.. sectionauthor:: Steven D'Aprano <steve+python@pearwood.info> +.. versionadded:: 3.6 + +.. testsetup:: + + from secrets import * + __name__ = '<doctest>' + +**Source code:** :source:`Lib/secrets.py` + +------------- + +The :mod:`secrets` module is used for generating cryptographically strong +random numbers suitable for managing data such as passwords, account +authentication, security tokens, and related secrets. + +In particularly, :mod:`secrets` should be used in preference to the +default pseudo-random number generator in the :mod:`random` module, which +is designed for modelling and simulation, not security or cryptography. + +.. seealso:: + + :pep:`506` + + +Random numbers +-------------- + +The :mod:`secrets` module provides access to the most secure source of +randomness that your operating system provides. + +.. class:: SystemRandom + + A class for generating random numbers using the highest-quality + sources provided by the operating system. See + :class:`random.SystemRandom` for additional details. + +.. function:: choice(sequence) + + Return a randomly-chosen element from a non-empty sequence. + +.. function:: randbelow(n) + + Return a random int in the range [0, *n*). + +.. function:: randbits(k) + + Return an int with *k* random bits. + + +Generating tokens +----------------- + +The :mod:`secrets` module provides functions for generating secure +tokens, suitable for applications such as password resets, +hard-to-guess URLs, and similar. + +.. function:: token_bytes([nbytes=None]) + + Return a random byte string containing *nbytes* number of bytes. + If *nbytes* is ``None`` or not supplied, a reasonable default is + used. + + .. doctest:: + + >>> token_bytes(16) #doctest:+SKIP + b'\xebr\x17D*t\xae\xd4\xe3S\xb6\xe2\xebP1\x8b' + + +.. function:: token_hex([nbytes=None]) + + Return a random text string, in hexadecimal. The string has *nbytes* + random bytes, each byte converted to two hex digits. If *nbytes* is + ``None`` or not supplied, a reasonable default is used. + + .. doctest:: + + >>> token_hex(16) #doctest:+SKIP + 'f9bf78b9a18ce6d46a0cd2b0b86df9da' + +.. function:: token_urlsafe([nbytes=None]) + + Return a random URL-safe text string, containing *nbytes* random + bytes. The text is Base64 encoded, so on average each byte results + in approximately 1.3 characters. If *nbytes* is ``None`` or not + supplied, a reasonable default is used. + + .. doctest:: + + >>> token_urlsafe(16) #doctest:+SKIP + 'Drmhze6EPcv0fN_81Bj-nA' + + +How many bytes should tokens use? +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +To be secure against +`brute-force attacks <https://en.wikipedia.org/wiki/Brute-force_attack>`_, +tokens need to have sufficient randomness. Unfortunately, what is +considered sufficient will necessarily increase as computers get more +powerful and able to make more guesses in a shorter period. As of 2015, +it is believed that 32 bytes (256 bits) of randomness is sufficient for +the typical use-case expected for the :mod:`secrets` module. + +For those who want to manage their own token length, you can explicitly +specify how much randomness is used for tokens by giving an :class:`int` +argument to the various ``token_*`` functions. That argument is taken +as the number of bytes of randomness to use. + +Otherwise, if no argument is provided, or if the argument is ``None``, +the ``token_*`` functions will use a reasonable default instead. + +.. note:: + + That default is subject to change at any time, including during + maintenance releases. + + +Other functions +--------------- + +.. function:: compare_digest(a, b) + + Return ``True`` if strings *a* and *b* are equal, otherwise ``False``, + in such a way as to reduce the risk of + `timing attacks <http://codahale.com/a-lesson-in-timing-attacks/>`_. + See :func:`hmac.compare_digest` for additional details. + + +Recipes and best practices +-------------------------- + +This section shows recipes and best practices for using :mod:`secrets` +to manage a basic level of security. + +Generate an eight-character alphanumeric password: + +.. testcode:: + + import string + alphabet = string.ascii_letters + string.digits + password = ''.join(choice(alphabet) for i in range(8)) + + +.. note:: + + Applications should not + `store passwords in a recoverable format <http://cwe.mitre.org/data/definitions/257.html>`_, + whether plain text or encrypted. They should be salted and hashed + using a cryptographically-strong one-way (irreversible) hash function. + + +Generate a ten-character alphanumeric password with at least one +lowercase character, at least one uppercase character, and at least +three digits: + +.. testcode:: + + import string + alphabet = string.ascii_letters + string.digits + while True: + password = ''.join(choice(alphabet) for i in range(10)) + if (any(c.islower() for c in password) + and any(c.isupper() for c in password) + and sum(c.isdigit() for c in password) >= 3): + break + + +Generate an `XKCD-style passphrase <http://xkcd.com/936/>`_: + +.. testcode:: + + # On standard Linux systems, use a convenient dictionary file. + # Other platforms may need to provide their own word-list. + with open('/usr/share/dict/words') as f: + words = [word.strip() for word in f] + password = ' '.join(choice(words) for i in range(4)) + + +Generate a hard-to-guess temporary URL containing a security token +suitable for password recovery applications: + +.. testcode:: + + url = 'https://mydomain.com/reset=' + token_urlsafe() + + + +.. + # This modeline must appear within the last ten lines of the file. + kate: indent-width 3; remove-trailing-space on; replace-tabs on; encoding utf-8; diff --git a/Doc/library/site.rst b/Doc/library/site.rst index 0a73f5abc6..43daf790b7 100644 --- a/Doc/library/site.rst +++ b/Doc/library/site.rst @@ -52,7 +52,8 @@ searched for site-packages; otherwise they won't. A path configuration file is a file whose name has the form :file:`{name}.pth` and exists in one of the four directories mentioned above; its contents are additional items (one per line) to be added to ``sys.path``. Non-existing items -are never added to ``sys.path``. No item is added to ``sys.path`` more than +are never added to ``sys.path``, and no check is made that the item refers to a +directory rather than a file. No item is added to ``sys.path`` more than once. Blank lines and lines beginning with ``#`` are skipped. Lines starting with ``import`` (followed by space or tab) are executed. diff --git a/Doc/library/smtpd.rst b/Doc/library/smtpd.rst index 977f9a8748..ad6bd3cc06 100644 --- a/Doc/library/smtpd.rst +++ b/Doc/library/smtpd.rst @@ -29,7 +29,7 @@ SMTPServer Objects .. class:: SMTPServer(localaddr, remoteaddr, data_size_limit=33554432,\ - map=None, enable_SMTPUTF8=False, decode_data=True) + map=None, enable_SMTPUTF8=False, decode_data=False) Create a new :class:`SMTPServer` object, which binds to local address *localaddr*. It will treat *remoteaddr* as an upstream SMTP relayer. It @@ -45,20 +45,19 @@ SMTPServer Objects global socket map is used. *enable_SMTPUTF8* determins whether the ``SMTPUTF8`` extension (as defined - in :RFC:`6531`) should be enabled. The default is ``False``. If set to - ``True``, *decode_data* must be ``False`` (otherwise an error is raised). + in :RFC:`6531`) should be enabled. The default is ``False``. When ``True``, ``SMTPUTF8`` is accepted as a parameter to the ``MAIL`` command and when present is passed to :meth:`process_message` in the - ``kwargs['mail_options']`` list. + ``kwargs['mail_options']`` list. *decode_data* and *enable_SMTPUTF8* + cannot be set to ``True`` at the same time. *decode_data* specifies whether the data portion of the SMTP transaction - should be decoded using UTF-8. The default is ``True`` for backward - compatibility reasons, but will change to ``False`` in Python 3.6; specify - the keyword value explicitly to avoid the :exc:`DeprecationWarning`. When - *decode_data* is set to ``False`` the server advertises the ``8BITMIME`` + should be decoded using UTF-8. When *decode_data* is ``False`` (the + default), the server advertises the ``8BITMIME`` extension (:rfc:`6152`), accepts the ``BODY=8BITMIME`` parameter to the ``MAIL`` command, and when present passes it to :meth:`process_message` - in the ``kwargs['mail_options']`` list. + in the ``kwargs['mail_options']`` list. *decode_data* and *enable_SMTPUTF8* + cannot be set to ``True`` at the same time. .. method:: process_message(peer, mailfrom, rcpttos, data, **kwargs) @@ -75,9 +74,8 @@ SMTPServer Objects will be a bytes object. *kwargs* is a dictionary containing additional information. It is empty - unless at least one of ``decode_data=False`` or ``enable_SMTPUTF8=True`` - was given as an init parameter, in which case it contains the following - keys: + if ``decode_data=True`` was given as an init argument, otherwise + it contains the following keys: *mail_options*: a list of all received parameters to the ``MAIL`` @@ -108,9 +106,12 @@ SMTPServer Objects *localaddr* and *remoteaddr* may now contain IPv6 addresses. .. versionadded:: 3.5 - the *decode_data* and *enable_SMTPUTF8* constructor arguments, and the - *kwargs* argument to :meth:`process_message` when one or more of these is - specified. + The *decode_data* and *enable_SMTPUTF8* constructor parameters, and the + *kwargs* parameter to :meth:`process_message` when *decode_data* is + ``False``. + + .. versionchanged:: 3.6 + *decode_data* is now ``False`` by default. DebuggingServer Objects @@ -150,7 +151,7 @@ SMTPChannel Objects ------------------- .. class:: SMTPChannel(server, conn, addr, data_size_limit=33554432,\ - map=None, enable_SMTPUTF8=False, decode_data=True) + map=None, enable_SMTPUTF8=False, decode_data=False) Create a new :class:`SMTPChannel` object which manages the communication between the server and a single SMTP client. @@ -162,22 +163,25 @@ SMTPChannel Objects limit. *enable_SMTPUTF8* determins whether the ``SMTPUTF8`` extension (as defined - in :RFC:`6531`) should be enabled. The default is ``False``. A - :exc:`ValueError` is raised if both *enable_SMTPUTF8* and *decode_data* are - set to ``True`` at the same time. + in :RFC:`6531`) should be enabled. The default is ``False``. + *decode_data* and *enable_SMTPUTF8* cannot be set to ``True`` at the same + time. A dictionary can be specified in *map* to avoid using a global socket map. *decode_data* specifies whether the data portion of the SMTP transaction - should be decoded using UTF-8. The default is ``True`` for backward - compatibility reasons, but will change to ``False`` in Python 3.6. Specify - the keyword value explicitly to avoid the :exc:`DeprecationWarning`. + should be decoded using UTF-8. The default is ``False``. + *decode_data* and *enable_SMTPUTF8* cannot be set to ``True`` at the same + time. To use a custom SMTPChannel implementation you need to override the :attr:`SMTPServer.channel_class` of your :class:`SMTPServer`. .. versionchanged:: 3.5 - the *decode_data* and *enable_SMTPUTF8* arguments were added. + The *decode_data* and *enable_SMTPUTF8* parameters were added. + + .. versionchanged:: 3.6 + *decode_data* is now ``False`` by default. The :class:`SMTPChannel` has the following instance variables: diff --git a/Doc/library/socket.rst b/Doc/library/socket.rst index 3aa1b138ca..0d52d82106 100644 --- a/Doc/library/socket.rst +++ b/Doc/library/socket.rst @@ -869,6 +869,10 @@ to sockets. it is recommended to :meth:`close` them explicitly, or to use a :keyword:`with` statement around them. + .. versionchanged:: 3.6 + :exc:`OSError` is now raised if an error occurs when the underlying + :c:func:`close` call is made. + .. note:: :meth:`close()` releases the resource associated with a connection but diff --git a/Doc/library/socketserver.rst b/Doc/library/socketserver.rst index 98d2c46701..dac928124f 100644 --- a/Doc/library/socketserver.rst +++ b/Doc/library/socketserver.rst @@ -52,11 +52,12 @@ handler class by subclassing the :class:`BaseRequestHandler` class and overriding its :meth:`~BaseRequestHandler.handle` method; this method will process incoming requests. Second, you must instantiate one of the server classes, passing it -the server's address and the request handler class. Then call the +the server's address and the request handler class. It is recommended to use +the server in a :keyword:`with` statement. Then call the :meth:`~BaseServer.handle_request` or :meth:`~BaseServer.serve_forever` method of the server object to process one or many requests. Finally, call :meth:`~BaseServer.server_close` -to close the socket. +to close the socket (unless you used a :keyword:`with` statement). When inheriting from :class:`ThreadingMixIn` for threaded connection behavior, you should explicitly declare how you want your threads to behave on an abrupt @@ -111,6 +112,8 @@ server classes. :class:`UDPServer`. Setting the various attributes also changes the behavior of the underlying server mechanism. + :class:`ForkingMixIn` and the Forking classes mentioned below are + only available on POSIX platforms that support :func:`~os.fork`. .. class:: ForkingTCPServer ForkingUDPServer @@ -304,7 +307,11 @@ Server Objects This function is called if the :meth:`~BaseRequestHandler.handle` method of a :attr:`RequestHandlerClass` instance raises an exception. The default action is to print the traceback to - standard output and continue handling further requests. + standard error and continue handling further requests. + + .. versionchanged:: 3.6 + Now only called for exceptions derived from the :exc:`Exception` + class. .. method:: handle_timeout() @@ -349,6 +356,11 @@ Server Objects default implementation always returns :const:`True`. + .. versionchanged:: 3.6 + Support for the :term:`context manager` protocol was added. Exiting the + context manager is equivalent to calling :meth:`server_close`. + + Request Handler Objects ----------------------- @@ -429,11 +441,10 @@ This is the server side:: HOST, PORT = "localhost", 9999 # Create the server, binding to localhost on port 9999 - server = socketserver.TCPServer((HOST, PORT), MyTCPHandler) - - # Activate the server; this will keep running until you - # interrupt the program with Ctrl-C - server.serve_forever() + with socketserver.TCPServer((HOST, PORT), MyTCPHandler) as server: + # Activate the server; this will keep running until you + # interrupt the program with Ctrl-C + server.serve_forever() An alternative request handler class that makes use of streams (file-like objects that simplify communication by providing the standard file interface):: @@ -521,8 +532,8 @@ This is the server side:: if __name__ == "__main__": HOST, PORT = "localhost", 9999 - server = socketserver.UDPServer((HOST, PORT), MyUDPHandler) - server.serve_forever() + with socketserver.UDPServer((HOST, PORT), MyUDPHandler) as server: + server.serve_forever() This is the client side:: @@ -581,22 +592,22 @@ An example for the :class:`ThreadingMixIn` class:: HOST, PORT = "localhost", 0 server = ThreadedTCPServer((HOST, PORT), ThreadedTCPRequestHandler) - ip, port = server.server_address + with server: + ip, port = server.server_address - # Start a thread with the server -- that thread will then start one - # more thread for each request - server_thread = threading.Thread(target=server.serve_forever) - # Exit the server thread when the main thread terminates - server_thread.daemon = True - server_thread.start() - print("Server loop running in thread:", server_thread.name) + # Start a thread with the server -- that thread will then start one + # more thread for each request + server_thread = threading.Thread(target=server.serve_forever) + # Exit the server thread when the main thread terminates + server_thread.daemon = True + server_thread.start() + print("Server loop running in thread:", server_thread.name) - client(ip, port, "Hello World 1") - client(ip, port, "Hello World 2") - client(ip, port, "Hello World 3") + client(ip, port, "Hello World 1") + client(ip, port, "Hello World 2") + client(ip, port, "Hello World 3") - server.shutdown() - server.server_close() + server.shutdown() The output of the example should look something like this:: @@ -610,3 +621,5 @@ The output of the example should look something like this:: The :class:`ForkingMixIn` class is used in the same way, except that the server will spawn a new process for each request. +Available only on POSIX platforms that support :func:`~os.fork`. + diff --git a/Doc/library/spwd.rst b/Doc/library/spwd.rst index 58be78f017..53f8c09e09 100644 --- a/Doc/library/spwd.rst +++ b/Doc/library/spwd.rst @@ -54,6 +54,9 @@ The following functions are defined: Return the shadow password database entry for the given user name. + .. versionchanged:: 3.6 + Raises a :exc:`PermissionError` instead of :exc:`KeyError` if the user + doesn't have privileges. .. function:: getspall() diff --git a/Doc/library/stdtypes.rst b/Doc/library/stdtypes.rst index 80f47793be..33bd7a124e 100644 --- a/Doc/library/stdtypes.rst +++ b/Doc/library/stdtypes.rst @@ -1453,8 +1453,8 @@ multiple fragments. For more information on the ``str`` class and its methods, see :ref:`textseq` and the :ref:`string-methods` section below. To output - formatted strings, see the :ref:`formatstrings` section. In addition, - see the :ref:`stringservices` section. + formatted strings, see the :ref:`f-strings` and :ref:`formatstrings` + sections. In addition, see the :ref:`stringservices` section. .. index:: @@ -2056,8 +2056,8 @@ expression support in the :mod:`re` module). .. index:: single: formatting, string (%) single: interpolation, string (%) - single: string; formatting - single: string; interpolation + single: string; formatting, printf + single: string; interpolation, printf single: printf-style formatting single: sprintf-style formatting single: % formatting @@ -2067,9 +2067,10 @@ expression support in the :mod:`re` module). The formatting operations described here exhibit a variety of quirks that lead to a number of common errors (such as failing to display tuples and - dictionaries correctly). Using the newer :meth:`str.format` interface - helps avoid these errors, and also provides a generally more powerful, - flexible and extensible approach to formatting text. + dictionaries correctly). Using the newer :ref:`formatted + string literals <f-strings>` or the :meth:`str.format` interface + helps avoid these errors. These alternatives also provide more powerful, + flexible and extensible approaches to formatting text. String objects have one unique built-in operation: the ``%`` operator (modulo). This is also known as the string *formatting* or *interpolation* operator. diff --git a/Doc/library/string.rst b/Doc/library/string.rst index d5d24301b6..c421c72d75 100644 --- a/Doc/library/string.rst +++ b/Doc/library/string.rst @@ -188,7 +188,9 @@ Format String Syntax The :meth:`str.format` method and the :class:`Formatter` class share the same syntax for format strings (although in the case of :class:`Formatter`, -subclasses can define their own format string syntax). +subclasses can define their own format string syntax). The syntax is +related to that of :ref:`formatted string literals <f-strings>`, but +there are differences. Format strings contain "replacement fields" surrounded by curly braces ``{}``. Anything that is not contained in braces is considered literal text, which is @@ -283,7 +285,8 @@ Format Specification Mini-Language "Format specifications" are used within replacement fields contained within a format string to define how individual values are presented (see -:ref:`formatstrings`). They can also be passed directly to the built-in +:ref:`formatstrings` and :ref:`f-strings`). +They can also be passed directly to the built-in :func:`format` function. Each formattable type may define how the format specification is to be interpreted. @@ -308,7 +311,8 @@ The general form of a *standard format specifier* is: If a valid *align* value is specified, it can be preceded by a *fill* character that can be any character and defaults to a space if omitted. It is not possible to use a literal curly brace ("``{``" or "``}``") as -the *fill* character when using the :meth:`str.format` +the *fill* character in a :ref:`formatted string literal +<f-strings>` or when using the :meth:`str.format` method. However, it is possible to insert a curly brace with a nested replacement field. This limitation doesn't affect the :func:`format` function. diff --git a/Doc/library/subprocess.rst b/Doc/library/subprocess.rst index 67bee40acb..6312487fdd 100644 --- a/Doc/library/subprocess.rst +++ b/Doc/library/subprocess.rst @@ -498,6 +498,10 @@ functions. .. versionchanged:: 3.2 Added context manager support. + .. versionchanged:: 3.6 + Popen destructor now emits a :exc:`ResourceWarning` warning if the child + process is still running. + Exceptions ^^^^^^^^^^ diff --git a/Doc/library/sys.rst b/Doc/library/sys.rst index 4f94124ea0..c92ad6abda 100644 --- a/Doc/library/sys.rst +++ b/Doc/library/sys.rst @@ -255,7 +255,7 @@ always available. (defaulting to zero), or another type of object. If it is an integer, zero is considered "successful termination" and any nonzero value is considered "abnormal termination" by shells and the like. Most systems require it to be - in the range 0-127, and produce undefined results otherwise. Some systems + in the range 0--127, and produce undefined results otherwise. Some systems have a convention for assigning specific meanings to specific exit codes, but these are generally underdeveloped; Unix programs generally use 2 for command line syntax errors and 1 for all other kind of errors. If another type of @@ -268,6 +268,11 @@ always available. the process when called from the main thread, and the exception is not intercepted. + .. versionchanged:: 3.6 + If an error occurs in the cleanup after the Python interpreter + has caught :exc:`SystemExit` (such as an error flushing buffered data + in the standard streams), the exit status is changed to 120. + .. data:: flags diff --git a/Doc/library/sysconfig.rst b/Doc/library/sysconfig.rst index 535ac54b3c..47f3900eeb 100644 --- a/Doc/library/sysconfig.rst +++ b/Doc/library/sysconfig.rst @@ -163,7 +163,7 @@ Other functions .. function:: get_python_version() Return the ``MAJOR.MINOR`` Python version number as a string. Similar to - ``sys.version[:3]``. + ``'%d.%d' % sys.version_info[:2]``. .. function:: get_platform() diff --git a/Doc/library/telnetlib.rst b/Doc/library/telnetlib.rst index 4040f72ee8..ce406ca2e6 100644 --- a/Doc/library/telnetlib.rst +++ b/Doc/library/telnetlib.rst @@ -43,6 +43,17 @@ Character), EL (Erase Line), GA (Go Ahead), SB (Subnegotiation Begin). :exc:`EOFError` when the end of the connection is read, because they can return an empty string for other reasons. See the individual descriptions below. + A :class:`Telnet` object is a context manager and can be used in a + :keyword:`with` statement. When the :keyword:`with` block ends, the + :meth:`close` method is called:: + + >>> from telnetlib import Telnet + >>> with Telnet('localhost', 23) as tn: + ... tn.interact() + ... + + .. versionchanged:: 3.6 Context manager support added + .. seealso:: diff --git a/Doc/library/test.rst b/Doc/library/test.rst index a5ce2ca880..d2649ccfc7 100644 --- a/Doc/library/test.rst +++ b/Doc/library/test.rst @@ -580,6 +580,48 @@ The :mod:`test.support` module defines the following functions: .. versionadded:: 3.5 +.. function:: check__all__(test_case, module, name_of_module=None, extra=(), blacklist=()) + + Assert that the ``__all__`` variable of *module* contains all public names. + + The module's public names (its API) are detected automatically + based on whether they match the public name convention and were defined in + *module*. + + The *name_of_module* argument can specify (as a string or tuple thereof) what + module(s) an API could be defined in in order to be detected as a public + API. One case for this is when *module* imports part of its public API from + other modules, possibly a C backend (like ``csv`` and its ``_csv``). + + The *extra* argument can be a set of names that wouldn't otherwise be automatically + detected as "public", like objects without a proper ``__module__`` + attribute. If provided, it will be added to the automatically detected ones. + + The *blacklist* argument can be a set of names that must not be treated as part of + the public API even though their names indicate otherwise. + + Example use:: + + import bar + import foo + import unittest + from test import support + + class MiscTestCase(unittest.TestCase): + def test__all__(self): + support.check__all__(self, foo) + + class OtherTestCase(unittest.TestCase): + def test__all__(self): + extra = {'BAR_CONST', 'FOO_CONST'} + blacklist = {'baz'} # Undocumented name. + # bar imports part of its API from _bar. + support.check__all__(self, bar, ('bar', '_bar'), + extra=extra, blacklist=blacklist) + + .. versionadded:: 3.6 + + The :mod:`test.support` module defines the following classes: .. class:: TransientResource(exc, **kwargs) diff --git a/Doc/library/time.rst b/Doc/library/time.rst index 8b53bbb0ed..c3c75d5526 100644 --- a/Doc/library/time.rst +++ b/Doc/library/time.rst @@ -636,11 +636,11 @@ The module defines the following functions and data items: it is possible to refer to February 29. :samp:`M{m}.{n}.{d}` - The *d*'th day (0 <= *d* <= 6) or week *n* of month *m* of the year (1 + The *d*'th day (0 <= *d* <= 6) of week *n* of month *m* of the year (1 <= *n* <= 5, 1 <= *m* <= 12, where week 5 means "the last *d* day in month *m*" which may occur in either the fourth or the fifth week). Week 1 is the first week in which the *d*'th day occurs. Day - zero is Sunday. + zero is a Sunday. ``time`` has the same format as ``offset`` except that no leading sign ('-' or '+') is allowed. The default, if time is not given, is 02:00:00. diff --git a/Doc/library/tracemalloc.rst b/Doc/library/tracemalloc.rst index 5feb2d9e89..9d1cb177d7 100644 --- a/Doc/library/tracemalloc.rst +++ b/Doc/library/tracemalloc.rst @@ -355,10 +355,32 @@ Functions See also the :func:`get_object_traceback` function. +DomainFilter +^^^^^^^^^^^^ + +.. class:: DomainFilter(inclusive: bool, domain: int) + + Filter traces of memory blocks by their address space (domain). + + .. versionadded:: 3.6 + + .. attribute:: inclusive + + If *inclusive* is ``True`` (include), match memory blocks allocated + in the address space :attr:`domain`. + + If *inclusive* is ``False`` (exclude), match memory blocks not allocated + in the address space :attr:`domain`. + + .. attribute:: domain + + Address space of a memory block (``int``). Read-only property. + + Filter ^^^^^^ -.. class:: Filter(inclusive: bool, filename_pattern: str, lineno: int=None, all_frames: bool=False) +.. class:: Filter(inclusive: bool, filename_pattern: str, lineno: int=None, all_frames: bool=False, domain: int=None) Filter on traces of memory blocks. @@ -378,9 +400,17 @@ Filter .. versionchanged:: 3.5 The ``'.pyo'`` file extension is no longer replaced with ``'.py'``. + .. versionchanged:: 3.6 + Added the :attr:`domain` attribute. + + + .. attribute:: domain + + Address space of a memory block (``int`` or ``None``). + .. attribute:: inclusive - If *inclusive* is ``True`` (include), only trace memory blocks allocated + If *inclusive* is ``True`` (include), only match memory blocks allocated in a file with a name matching :attr:`filename_pattern` at line number :attr:`lineno`. @@ -395,7 +425,7 @@ Filter .. attribute:: filename_pattern - Filename pattern of the filter (``str``). + Filename pattern of the filter (``str``). Read-only property. .. attribute:: all_frames @@ -458,14 +488,17 @@ Snapshot .. method:: filter_traces(filters) Create a new :class:`Snapshot` instance with a filtered :attr:`traces` - sequence, *filters* is a list of :class:`Filter` instances. If *filters* - is an empty list, return a new :class:`Snapshot` instance with a copy of - the traces. + sequence, *filters* is a list of :class:`DomainFilter` and + :class:`Filter` instances. If *filters* is an empty list, return a new + :class:`Snapshot` instance with a copy of the traces. All inclusive filters are applied at once, a trace is ignored if no inclusive filters match it. A trace is ignored if at least one exclusive filter matches it. + .. versionchanged:: 3.6 + :class:`DomainFilter` instances are now also accepted in *filters*. + .. classmethod:: load(filename) diff --git a/Doc/library/typing.rst b/Doc/library/typing.rst index 25d7794b58..605d0130ac 100644 --- a/Doc/library/typing.rst +++ b/Doc/library/typing.rst @@ -347,11 +347,15 @@ The module defines the following classes, functions and decorators: .. class:: Iterable(Generic[T_co]) - A generic version of the :class:`collections.abc.Iterable`. + A generic version of :class:`collections.abc.Iterable`. .. class:: Iterator(Iterable[T_co]) - A generic version of the :class:`collections.abc.Iterator`. + A generic version of :class:`collections.abc.Iterator`. + +.. class:: Reversible(Iterable[T_co]) + + A generic version of :class:`collections.abc.Reversible`. .. class:: SupportsInt @@ -371,11 +375,6 @@ The module defines the following classes, functions and decorators: An ABC with one abstract method ``__round__`` that is covariant in its return type. -.. class:: Reversible - - An ABC with one abstract method ``__reversed__`` returning - an ``Iterator[T_co]``. - .. class:: Container(Generic[T_co]) A generic version of :class:`collections.abc.Container`. @@ -396,7 +395,7 @@ The module defines the following classes, functions and decorators: A generic version of :class:`collections.abc.MutableMapping`. -.. class:: Sequence(Sized, Iterable[T_co], Container[T_co]) +.. class:: Sequence(Sized, Reversible[T_co], Container[T_co]) A generic version of :class:`collections.abc.Sequence`. @@ -451,6 +450,12 @@ The module defines the following classes, functions and decorators: A generic version of :class:`collections.abc.ValuesView`. +.. class:: ContextManager(Generic[T_co]) + + A generic version of :class:`contextlib.AbstractContextManager`. + + .. versionadded:: 3.6 + .. class:: Dict(dict, MutableMapping[KT, VT]) A generic version of :class:`dict`. diff --git a/Doc/library/unittest.mock.rst b/Doc/library/unittest.mock.rst index 929ceadbd7..f2ebf11311 100644 --- a/Doc/library/unittest.mock.rst +++ b/Doc/library/unittest.mock.rst @@ -259,6 +259,34 @@ the *new_callable* argument to :func:`patch`. used to set attributes on the mock after it is created. See the :meth:`configure_mock` method for details. + .. method:: assert_called(*args, **kwargs) + + Assert that the mock was called at least once. + + >>> mock = Mock() + >>> mock.method() + <Mock name='mock.method()' id='...'> + >>> mock.method.assert_called() + + .. versionadded:: 3.6 + + .. method:: assert_called_once(*args, **kwargs) + + Assert that the mock was called exactly once. + + >>> mock = Mock() + >>> mock.method() + <Mock name='mock.method()' id='...'> + >>> mock.method.assert_called_once() + >>> mock.method() + <Mock name='mock.method()' id='...'> + >>> mock.method.assert_called_once() + Traceback (most recent call last): + ... + AssertionError: Expected 'method' to have been called once. Called 2 times. + + .. versionadded:: 3.6 + .. method:: assert_called_with(*args, **kwargs) @@ -336,7 +364,7 @@ the *new_callable* argument to :func:`patch`. .. versionadded:: 3.5 - .. method:: reset_mock() + .. method:: reset_mock(*, return_value=False, side_effect=False) The reset_mock method resets all the call attributes on a mock object: @@ -348,12 +376,20 @@ the *new_callable* argument to :func:`patch`. >>> mock.called False + .. versionchanged:: 3.6 + Added two keyword only argument to the reset_mock function. + This can be useful where you want to make a series of assertions that reuse the same object. Note that :meth:`reset_mock` *doesn't* clear the return value, :attr:`side_effect` or any child attributes you have - set using normal assignment. Child mocks and the return value mock + set using normal assignment by default. In case you want to reset + *return_value* or :attr:`side_effect`, then pass the corresponding + parameter as ``True``. Child mocks and the return value mock (if any) are reset as well. + .. note:: *return_value*, and :attr:`side_effect` are keyword only + argument. + .. method:: mock_add_spec(spec, spec_set=False) diff --git a/Doc/library/unittest.rst b/Doc/library/unittest.rst index 8482f207bd..55a6aaff67 100644 --- a/Doc/library/unittest.rst +++ b/Doc/library/unittest.rst @@ -1388,9 +1388,9 @@ Test cases Add a function to be called after :meth:`tearDown` to cleanup resources used during the test. Functions will be called in reverse order to the - order they are added (LIFO). They are called with any arguments and - keyword arguments passed into :meth:`addCleanup` when they are - added. + order they are added (:abbr:`LIFO (last-in, first-out)`). They + are called with any arguments and keyword arguments passed into + :meth:`addCleanup` when they are added. If :meth:`setUp` fails, meaning that :meth:`tearDown` is not called, then any cleanup functions added will still be called. diff --git a/Doc/library/urllib.parse.rst b/Doc/library/urllib.parse.rst index 9eb0a93f3c..a8e4a19e97 100644 --- a/Doc/library/urllib.parse.rst +++ b/Doc/library/urllib.parse.rst @@ -115,8 +115,9 @@ or on combining URL components into a URL string. | | | if present | | +------------------+-------+--------------------------+----------------------+ - See section :ref:`urlparse-result-object` for more information on the result - object. + Reading the :attr:`port` attribute will raise a :exc:`ValueError` if + an invalid port is specified in the URL. See section + :ref:`urlparse-result-object` for more information on the result object. .. versionchanged:: 3.2 Added IPv6 URL parsing capabilities. @@ -126,6 +127,10 @@ or on combining URL components into a URL string. false), in accordance with :rfc:`3986`. Previously, a whitelist of schemes that support fragments existed. + .. versionchanged:: 3.6 + Out-of-range port numbers now raise :exc:`ValueError`, instead of + returning :const:`None`. + .. function:: parse_qs(qs, keep_blank_values=False, strict_parsing=False, encoding='utf-8', errors='replace') @@ -228,8 +233,13 @@ or on combining URL components into a URL string. | | | if present | | +------------------+-------+-------------------------+----------------------+ - See section :ref:`urlparse-result-object` for more information on the result - object. + Reading the :attr:`port` attribute will raise a :exc:`ValueError` if + an invalid port is specified in the URL. See section + :ref:`urlparse-result-object` for more information on the result object. + + .. versionchanged:: 3.6 + Out-of-range port numbers now raise :exc:`ValueError`, instead of + returning :const:`None`. .. function:: urlunsplit(parts) diff --git a/Doc/library/urllib.robotparser.rst b/Doc/library/urllib.robotparser.rst index f179de2f92..c2e1bef8bb 100644 --- a/Doc/library/urllib.robotparser.rst +++ b/Doc/library/urllib.robotparser.rst @@ -53,15 +53,41 @@ structure of :file:`robots.txt` files, see http://www.robotstxt.org/orig.html. Sets the time the ``robots.txt`` file was last fetched to the current time. + .. method:: crawl_delay(useragent) -The following example demonstrates basic use of the RobotFileParser class. + Returns the value of the ``Crawl-delay`` parameter from ``robots.txt`` + for the *useragent* in question. If there is no such parameter or it + doesn't apply to the *useragent* specified or the ``robots.txt`` entry + for this parameter has invalid syntax, return ``None``. + + .. versionadded:: 3.6 + + .. method:: request_rate(useragent) + + Returns the contents of the ``Request-rate`` parameter from + ``robots.txt`` in the form of a :func:`~collections.namedtuple` + ``(requests, seconds)``. If there is no such parameter or it doesn't + apply to the *useragent* specified or the ``robots.txt`` entry for this + parameter has invalid syntax, return ``None``. + + .. versionadded:: 3.6 + + +The following example demonstrates basic use of the :class:`RobotFileParser` +class:: >>> import urllib.robotparser >>> rp = urllib.robotparser.RobotFileParser() >>> rp.set_url("http://www.musi-cal.com/robots.txt") >>> rp.read() + >>> rrate = rp.request_rate("*") + >>> rrate.requests + 3 + >>> rrate.seconds + 20 + >>> rp.crawl_delay("*") + 6 >>> rp.can_fetch("*", "http://www.musi-cal.com/cgi-bin/search?city=San+Francisco") False >>> rp.can_fetch("*", "http://www.musi-cal.com/") True - diff --git a/Doc/library/warnings.rst b/Doc/library/warnings.rst index 037f11d357..2bd11a6b01 100644 --- a/Doc/library/warnings.rst +++ b/Doc/library/warnings.rst @@ -300,7 +300,7 @@ Available Functions ------------------- -.. function:: warn(message, category=None, stacklevel=1) +.. function:: warn(message, category=None, stacklevel=1, source=None) Issue a warning, or maybe ignore it or raise an exception. The *category* argument, if given, must be a warning category class (see above); it defaults to @@ -318,8 +318,14 @@ Available Functions source of :func:`deprecation` itself (since the latter would defeat the purpose of the warning message). + *source*, if supplied, is the destroyed object which emitted a + :exc:`ResourceWarning`. -.. function:: warn_explicit(message, category, filename, lineno, module=None, registry=None, module_globals=None) + .. versionchanged:: 3.6 + Added *source* parameter. + + +.. function:: warn_explicit(message, category, filename, lineno, module=None, registry=None, module_globals=None, source=None) This is a low-level interface to the functionality of :func:`warn`, passing in explicitly the message, category, filename and line number, and optionally the @@ -335,6 +341,12 @@ Available Functions source for modules found in zipfiles or other non-filesystem import sources). + *source*, if supplied, is the destroyed object which emitted a + :exc:`ResourceWarning`. + + .. versionchanged:: 3.6 + Add the *source* parameter. + .. function:: showwarning(message, category, filename, lineno, file=None, line=None) diff --git a/Doc/library/winreg.rst b/Doc/library/winreg.rst index 94378b21d5..8f8cc680fc 100644 --- a/Doc/library/winreg.rst +++ b/Doc/library/winreg.rst @@ -633,7 +633,7 @@ For more information, see `Registry Value Types .. data:: REG_DWORD_LITTLE_ENDIAN - A 32-bit number in little-endian format. + A 32-bit number in little-endian format. Equivalent to :const:`REG_DWORD`. .. data:: REG_DWORD_BIG_ENDIAN @@ -657,6 +657,18 @@ For more information, see `Registry Value Types No defined value type. +.. data:: REG_QWORD + + A 64-bit number. + + .. versionadded:: 3.6 + +.. data:: REG_QWORD_LITTLE_ENDIAN + + A 64-bit number in little-endian format. Equivalent to :const:`REG_QWORD`. + + .. versionadded:: 3.6 + .. data:: REG_RESOURCE_LIST A device-driver resource list. diff --git a/Doc/library/wsgiref.rst b/Doc/library/wsgiref.rst index 3253f48ea2..e15d91953d 100644 --- a/Doc/library/wsgiref.rst +++ b/Doc/library/wsgiref.rst @@ -131,9 +131,9 @@ parameter expect a WSGI-compliant dictionary to be supplied; please see for key, value in environ.items()] return ret - httpd = make_server('', 8000, simple_app) - print("Serving on port 8000...") - httpd.serve_forever() + with make_server('', 8000, simple_app) as httpd: + print("Serving on port 8000...") + httpd.serve_forever() In addition to the environment functions above, the :mod:`wsgiref.util` module @@ -283,14 +283,14 @@ request. (E.g., using the :func:`shift_path_info` function from from wsgiref.simple_server import make_server, demo_app - httpd = make_server('', 8000, demo_app) - print("Serving HTTP on port 8000...") + with make_server('', 8000, demo_app) as httpd: + print("Serving HTTP on port 8000...") - # Respond to requests until process is killed - httpd.serve_forever() + # Respond to requests until process is killed + httpd.serve_forever() - # Alternative: serve one request, then exit - httpd.handle_request() + # Alternative: serve one request, then exit + httpd.handle_request() .. function:: demo_app(environ, start_response) @@ -430,9 +430,9 @@ Paste" library. # This is the application wrapped in a validator validator_app = validator(simple_app) - httpd = make_server('', 8000, validator_app) - print("Listening on port 8000....") - httpd.serve_forever() + with make_server('', 8000, validator_app) as httpd: + print("Listening on port 8000....") + httpd.serve_forever() :mod:`wsgiref.handlers` -- server/gateway base classes @@ -772,8 +772,8 @@ This is a working "Hello World" WSGI application:: # The returned object is going to be printed return [b"Hello World"] - httpd = make_server('', 8000, hello_world_app) - print("Serving on port 8000...") + with make_server('', 8000, hello_world_app) as httpd: + print("Serving on port 8000...") - # Serve until process is killed - httpd.serve_forever() + # Serve until process is killed + httpd.serve_forever() diff --git a/Doc/library/xmlrpc.server.rst b/Doc/library/xmlrpc.server.rst index 680db41f21..ca80aab2a8 100644 --- a/Doc/library/xmlrpc.server.rst +++ b/Doc/library/xmlrpc.server.rst @@ -147,29 +147,29 @@ Server code:: rpc_paths = ('/RPC2',) # Create server - server = SimpleXMLRPCServer(("localhost", 8000), - requestHandler=RequestHandler) - server.register_introspection_functions() + with SimpleXMLRPCServer(("localhost", 8000), + requestHandler=RequestHandler) as server: + server.register_introspection_functions() - # Register pow() function; this will use the value of - # pow.__name__ as the name, which is just 'pow'. - server.register_function(pow) + # Register pow() function; this will use the value of + # pow.__name__ as the name, which is just 'pow'. + server.register_function(pow) - # Register a function under a different name - def adder_function(x,y): - return x + y - server.register_function(adder_function, 'add') + # Register a function under a different name + def adder_function(x,y): + return x + y + server.register_function(adder_function, 'add') - # Register an instance; all the methods of the instance are - # published as XML-RPC methods (in this case, just 'mul'). - class MyFuncs: - def mul(self, x, y): - return x * y + # Register an instance; all the methods of the instance are + # published as XML-RPC methods (in this case, just 'mul'). + class MyFuncs: + def mul(self, x, y): + return x * y - server.register_instance(MyFuncs()) + server.register_instance(MyFuncs()) - # Run the server's main loop - server.serve_forever() + # Run the server's main loop + server.serve_forever() The following client code will call the methods made available by the preceding server:: @@ -206,18 +206,17 @@ a server allowing dotted names and registering a multicall function. def getCurrentTime(): return datetime.datetime.now() - server = SimpleXMLRPCServer(("localhost", 8000)) - server.register_function(pow) - server.register_function(lambda x,y: x+y, 'add') - server.register_instance(ExampleService(), allow_dotted_names=True) - server.register_multicall_functions() - print('Serving XML-RPC on localhost port 8000') - try: - server.serve_forever() - except KeyboardInterrupt: - print("\nKeyboard interrupt received, exiting.") - server.server_close() - sys.exit(0) + with SimpleXMLRPCServer(("localhost", 8000)) as server: + server.register_function(pow) + server.register_function(lambda x,y: x+y, 'add') + server.register_instance(ExampleService(), allow_dotted_names=True) + server.register_multicall_functions() + print('Serving XML-RPC on localhost port 8000') + try: + server.serve_forever() + except KeyboardInterrupt: + print("\nKeyboard interrupt received, exiting.") + sys.exit(0) This ExampleService demo can be invoked from the command line:: diff --git a/Doc/library/zipfile.rst b/Doc/library/zipfile.rst index 9b0d18a365..f5e161e6f4 100644 --- a/Doc/library/zipfile.rst +++ b/Doc/library/zipfile.rst @@ -207,15 +207,15 @@ ZipFile Objects .. index:: single: universal newlines; zipfile.ZipFile.open method -.. method:: ZipFile.open(name, mode='r', pwd=None) +.. method:: ZipFile.open(name, mode='r', pwd=None, *, force_zip64=False) - Extract a member from the archive as a file-like object (ZipExtFile). *name* - is the name of the file in the archive, or a :class:`ZipInfo` object. The + Access a member of the archive as a file-like object. *name* + is the name of the file in the archive, or a :class:`ZipInfo` object. The *mode* parameter, if included, must be one of the following: ``'r'`` (the - default), ``'U'``, or ``'rU'``. Choosing ``'U'`` or ``'rU'`` will enable - :term:`universal newlines` support in the read-only object. *pwd* is the - password used for encrypted files. Calling :meth:`.open` on a closed - ZipFile will raise a :exc:`RuntimeError`. + default), ``'U'``, ``'rU'`` or ``'w'``. Choosing ``'U'`` or ``'rU'`` will + enable :term:`universal newlines` support in the read-only object. *pwd* is + the password used to decrypt encrypted ZIP files. Calling :meth:`.open` on + a closed ZipFile will raise a :exc:`RuntimeError`. :meth:`~ZipFile.open` is also a context manager and therefore supports the :keyword:`with` statement:: @@ -224,17 +224,23 @@ ZipFile Objects with myzip.open('eggs.txt') as myfile: print(myfile.read()) - .. note:: - - The file-like object is read-only and provides the following methods: - :meth:`~io.BufferedIOBase.read`, :meth:`~io.IOBase.readline`, - :meth:`~io.IOBase.readlines`, :meth:`__iter__`, - :meth:`~iterator.__next__`. + With *mode* ``'r'``, ``'U'`` or ``'rU'``, the file-like object + (``ZipExtFile``) is read-only and provides the following methods: + :meth:`~io.BufferedIOBase.read`, :meth:`~io.IOBase.readline`, + :meth:`~io.IOBase.readlines`, :meth:`__iter__`, + :meth:`~iterator.__next__`. These objects can operate independently of + the ZipFile. - .. note:: + With ``mode='w'``, a writable file handle is returned, which supports the + :meth:`~io.BufferedIOBase.write` method. While a writable file handle is open, + attempting to read or write other files in the ZIP file will raise a + :exc:`RuntimeError`. - Objects returned by :meth:`.open` can operate independently of the - ZipFile. + When writing a file, if the file size is not known in advance but may exceed + 2 GiB, pass ``force_zip64=True`` to ensure that the header format is + capable of supporting large files. If the file size is known in advance, + construct a :class:`ZipInfo` object with :attr:`~ZipInfo.file_size` set, and + use that as the *name* parameter. .. note:: @@ -246,6 +252,10 @@ ZipFile Objects The ``'U'`` or ``'rU'`` mode. Use :class:`io.TextIOWrapper` for reading compressed text files in :term:`universal newlines` mode. + .. versionchanged:: 3.6 + :meth:`open` can now be used to write files into the archive with the + ``mode='w'`` option. + .. method:: ZipFile.extract(member, path=None, pwd=None) Extract a member from the archive to the current working directory; *member* @@ -464,7 +474,31 @@ Instances of the :class:`ZipInfo` class are returned by the :meth:`.getinfo` and :meth:`.infolist` methods of :class:`ZipFile` objects. Each object stores information about a single member of the ZIP archive. -Instances have the following attributes: +There is one classmethod to make a :class:`ZipInfo` instance for a filesystem +file: + +.. classmethod:: ZipInfo.from_file(filename, arcname=None) + + Construct a :class:`ZipInfo` instance for a file on the filesystem, in + preparation for adding it to a zip file. + + *filename* should be the path to a file or directory on the filesystem. + + If *arcname* is specified, it is used as the name within the archive. + If *arcname* is not specified, the name will be the same as *filename*, but + with any drive letter and leading path separators removed. + + .. versionadded:: 3.6 + +Instances have the following methods and attributes: + +.. method:: ZipInfo.is_dir() + + Return True if this archive member is a directory. + + This uses the entry's name: directories should always end with ``/``. + + .. versionadded:: 3.6 .. attribute:: ZipInfo.filename @@ -573,4 +607,5 @@ Instances have the following attributes: Size of the uncompressed file. + .. _PKZIP Application Note: https://pkware.cachefly.net/webdocs/casestudies/APPNOTE.TXT diff --git a/Doc/library/zlib.rst b/Doc/library/zlib.rst index b7ca558932..9f6fbf8e4e 100644 --- a/Doc/library/zlib.rst +++ b/Doc/library/zlib.rst @@ -46,14 +46,19 @@ The available exception and functions in this module are: platforms, use ``adler32(data) & 0xffffffff``. -.. function:: compress(data[, level]) +.. function:: compress(data, level=-1) Compresses the bytes in *data*, returning a bytes object containing compressed data. - *level* is an integer from ``0`` to ``9`` controlling the level of compression; + *level* is an integer from ``0`` to ``9`` or ``-1`` controlling the level of compression; ``1`` is fastest and produces the least compression, ``9`` is slowest and - produces the most. ``0`` is no compression. The default value is ``6``. + produces the most. ``0`` is no compression. The default value is ``-1`` + (Z_DEFAULT_COMPRESSION). Z_DEFAULT_COMPRESSION represents a default + compromise between speed and compression (currently equivalent to level 6). Raises the :exc:`error` exception if any error occurs. + .. versionchanged:: 3.6 + Keyword arguments are now supported. + .. function:: compressobj(level=-1, method=DEFLATED, wbits=15, memLevel=8, strategy=Z_DEFAULT_STRATEGY[, zdict]) diff --git a/Doc/reference/compound_stmts.rst b/Doc/reference/compound_stmts.rst index 8047673e19..1a296923b2 100644 --- a/Doc/reference/compound_stmts.rst +++ b/Doc/reference/compound_stmts.rst @@ -471,10 +471,10 @@ A function definition defines a user-defined function object (see section decorators: `decorator`+ decorator: "@" `dotted_name` ["(" [`argument_list` [","]] ")"] NEWLINE dotted_name: `identifier` ("." `identifier`)* - parameter_list: (`defparameter` ",")* - : | "*" [`parameter`] ("," `defparameter`)* ["," "**" `parameter`] - : | "**" `parameter` - : | `defparameter` [","] ) + parameter_list: `defparameter` ("," `defparameter`)* ["," [`parameter_list_starargs`]] + : | `parameter_list_starargs` + parameter_list_starargs: "*" [`parameter`] ("," `defparameter`)* ["," ["**" `parameter` [","]]] + : | "**" `parameter` [","] parameter: `identifier` [":" `expression`] defparameter: `parameter` ["=" `expression`] funcname: `identifier` diff --git a/Doc/reference/datamodel.rst b/Doc/reference/datamodel.rst index 3ddbd622d8..c22c8ad557 100644 --- a/Doc/reference/datamodel.rst +++ b/Doc/reference/datamodel.rst @@ -1234,8 +1234,9 @@ Basic customization .. method:: object.__format__(self, format_spec) - Called by the :func:`format` built-in function (and by extension, the - :meth:`str.format` method of class :class:`str`) to produce a "formatted" + Called by the :func:`format` built-in function, + and by extension, evaluation of :ref:`formatted string literals + <f-strings>` and the :meth:`str.format` method, to produce a "formatted" string representation of an object. The ``format_spec`` argument is a string that contains a description of the formatting options desired. The interpretation of the ``format_spec`` argument is up to the type diff --git a/Doc/reference/import.rst b/Doc/reference/import.rst index 2144c1fa35..56049ce3d6 100644 --- a/Doc/reference/import.rst +++ b/Doc/reference/import.rst @@ -554,19 +554,30 @@ the module. details. This attribute is used instead of ``__name__`` to calculate explicit - relative imports for main modules, as defined in :pep:`366`. + relative imports for main modules, as defined in :pep:`366`. It is + expected to have the same value as ``__spec__.parent``. + + .. versionchanged:: 3.6 + The value of ``__package__`` is expected to be the same as + ``__spec__.parent``. .. attribute:: __spec__ The ``__spec__`` attribute must be set to the module spec that was - used when importing the module. This is used primarily for - introspection and during reloading. Setting ``__spec__`` + used when importing the module. Setting ``__spec__`` appropriately applies equally to :ref:`modules initialized during interpreter startup <programs>`. The one exception is ``__main__``, where ``__spec__`` is :ref:`set to None in some cases <main_spec>`. + When ``__package__`` is not defined, ``__spec__.parent`` is used as + a fallback. + .. versionadded:: 3.4 + .. versionchanged:: 3.6 + ``__spec__.parent`` is used as a fallback when ``__package__`` is + not defined. + .. attribute:: __path__ If the module is a package (either regular or namespace), the module diff --git a/Doc/reference/lexical_analysis.rst b/Doc/reference/lexical_analysis.rst index 71964d71e6..fa65c0c636 100644 --- a/Doc/reference/lexical_analysis.rst +++ b/Doc/reference/lexical_analysis.rst @@ -405,7 +405,8 @@ String literals are described by the following lexical definitions: .. productionlist:: stringliteral: [`stringprefix`](`shortstring` | `longstring`) - stringprefix: "r" | "u" | "R" | "U" + stringprefix: "r" | "u" | "R" | "U" | "f" | "F" + : | "fr" | "Fr" | "fR" | "FR" | "rf" | "rF" | "Rf" | "RF" shortstring: "'" `shortstringitem`* "'" | '"' `shortstringitem`* '"' longstring: "'''" `longstringitem`* "'''" | '"""' `longstringitem`* '"""' shortstringitem: `shortstringchar` | `stringescapeseq` @@ -464,6 +465,11 @@ is not supported. to simplify the maintenance of dual Python 2.x and 3.x codebases. See :pep:`414` for more information. +A string literal with ``'f'`` or ``'F'`` in its prefix is a +:dfn:`formatted string literal`; see :ref:`f-strings`. The ``'f'`` may be +combined with ``'r'``, but not with ``'b'`` or ``'u'``, therefore raw +formatted strings are possible, but formatted bytes literals are not. + In triple-quoted literals, unescaped newlines and quotes are allowed (and are retained), except that three unescaped quotes in a row terminate the literal. (A "quote" is the character used to open the literal, i.e. either ``'`` or ``"``.) @@ -583,7 +589,105 @@ comments to parts of strings, for example:: Note that this feature is defined at the syntactical level, but implemented at compile time. The '+' operator must be used to concatenate string expressions at run time. Also note that literal concatenation can use different quoting -styles for each component (even mixing raw strings and triple quoted strings). +styles for each component (even mixing raw strings and triple quoted strings), +and formatted string literals may be concatenated with plain string literals. + + +.. index:: + single: formatted string literal + single: interpolated string literal + single: string; formatted literal + single: string; interpolated literal + single: f-string +.. _f-strings: + +Formatted string literals +------------------------- + +.. versionadded:: 3.6 + +A :dfn:`formatted string literal` or :dfn:`f-string` is a string literal +that is prefixed with ``'f'`` or ``'F'``. These strings may contain +replacement fields, which are expressions delimited by curly braces ``{}``. +While other string literals always have a constant value, formatted strings +are really expressions evaluated at run time. + +Escape sequences are decoded like in ordinary string literals (except when +a literal is also marked as a raw string). After decoding, the grammar +for the contents of the string is: + +.. productionlist:: + f_string: (`literal_char` | "{{" | "}}" | `replacement_field`)* + replacement_field: "{" `f_expression` ["!" `conversion`] [":" `format_spec`] "}" + f_expression: `conditional_expression` ("," `conditional_expression`)* [","] + : | `yield_expression` + conversion: "s" | "r" | "a" + format_spec: (`literal_char` | NULL | `replacement_field`)* + literal_char: <any code point except "{", "}" or NULL> + +The parts of the string outside curly braces are treated literally, +except that any doubled curly braces ``'{{'`` or ``'}}'`` are replaced +with the corresponding single curly brace. A single opening curly +bracket ``'{'`` marks a replacement field, which starts with a +Python expression. After the expression, there may be a conversion field, +introduced by an exclamation point ``'!'``. A format specifier may also +be appended, introduced by a colon ``':'``. A replacement field ends +with a closing curly bracket ``'}'``. + +Expressions in formatted string literals are treated like regular +Python expressions surrounded by parentheses, with a few exceptions. +An empty expression is not allowed, and a :keyword:`lambda` expression +must be surrounded by explicit parentheses. Replacement expressions +can contain line breaks (e.g. in triple-quoted strings), but they +cannot contain comments. Each expression is evaluated in the context +where the formatted string literal appears, in order from left to right. + +If a conversion is specified, the result of evaluating the expression +is converted before formatting. Conversion ``'!s'`` calls :func:`str` on +the result, ``'!r'`` calls :func:`repr`, and ``'!a'`` calls :func:`ascii`. + +The result is then formatted using the :func:`format` protocol. The +format specifier is passed to the :meth:`__format__` method of the +expression or conversion result. An empty string is passed when the +format specifier is omitted. The formatted result is then included in +the final value of the whole string. + +Top-level format specifiers may include nested replacement fields. +These nested fields may include their own conversion fields and +format specifiers, but may not include more deeply-nested replacement fields. + +Formatted string literals may be concatenated, but replacement fields +cannot be split across literals. + +Some examples of formatted string literals:: + + >>> name = "Fred" + >>> f"He said his name is {name!r}." + "He said his name is 'Fred'." + >>> f"He said his name is {repr(name)}." # repr() is equivalent to !r + "He said his name is 'Fred'." + >>> width = 10 + >>> precision = 4 + >>> value = decimal.Decimal("12.34567") + >>> f"result: {value:{width}.{precision}}" # nested fields + 'result: 12.35' + +A consequence of sharing the same syntax as regular string literals is +that characters in the replacement fields must not conflict with the +quoting used in the outer formatted string literal. Also, escape +sequences normally apply to the outer formatted string literal, +rather than inner string literals:: + + f"abc {a["x"]} def" # error: outer string literal ended prematurely + f"abc {a[\"x\"]} def" # workaround: escape the inner quotes + f"abc {a['x']} def" # workaround: use different quoting + + f"newline: {ord('\n')}" # error: literal line break in inner string + f"newline: {ord('\\n')}" # workaround: double escaping + fr"newline: {ord('\n')}" # workaround: raw outer string + +See also :pep:`498` for the proposal that added formatted string literals, +and :meth:`str.format`, which uses a related format string mechanism. .. _numbers: diff --git a/Doc/reference/simple_stmts.rst b/Doc/reference/simple_stmts.rst index 7d71752936..59493c3aed 100644 --- a/Doc/reference/simple_stmts.rst +++ b/Doc/reference/simple_stmts.rst @@ -84,7 +84,7 @@ attributes or items of mutable objects: assignment_stmt: (`target_list` "=")+ (`expression_list` | `yield_expression`) target_list: `target` ("," `target`)* [","] target: `identifier` - : | "(" `target_list` ")" + : | "(" [`target_list`] ")" : | "[" [`target_list`] "]" : | `attributeref` : | `subscription` diff --git a/Doc/tools/extensions/pyspecific.py b/Doc/tools/extensions/pyspecific.py index 63112830ba..7986017d01 100644 --- a/Doc/tools/extensions/pyspecific.py +++ b/Doc/tools/extensions/pyspecific.py @@ -34,7 +34,7 @@ import suspicious ISSUE_URI = 'https://bugs.python.org/issue%s' -SOURCE_URI = 'https://hg.python.org/cpython/file/3.5/%s' +SOURCE_URI = 'https://hg.python.org/cpython/file/default/%s' # monkey-patch reST parser to disable alphabetic and roman enumerated lists from docutils.parsers.rst.states import Body diff --git a/Doc/tools/susp-ignored.csv b/Doc/tools/susp-ignored.csv index c394af335a..46cc2f17ab 100644 --- a/Doc/tools/susp-ignored.csv +++ b/Doc/tools/susp-ignored.csv @@ -272,6 +272,7 @@ whatsnew/3.2,,:feed,>>> urllib.parse.urlparse('http://[dead:beef:cafe:5417:affe: whatsnew/3.2,,:gz,">>> with tarfile.open(name='myarchive.tar.gz', mode='w:gz') as tf:" whatsnew/3.2,,:location,zope9-location = ${zope9:location} whatsnew/3.2,,:prefix,zope-conf = ${custom:prefix}/etc/zope.conf +whatsnew/changelog,,:version,import sys; I = version[:version.index(' ')] whatsnew/changelog,,:gz,": TarFile opened with external fileobj and ""w:gz"" mode didn't" whatsnew/changelog,,::,": Use ""127.0.0.1"" or ""::1"" instead of ""localhost"" as much as" library/tarfile,149,:xz,'x:xz' diff --git a/Doc/tutorial/controlflow.rst b/Doc/tutorial/controlflow.rst index ddc08552ed..b03b55324d 100644 --- a/Doc/tutorial/controlflow.rst +++ b/Doc/tutorial/controlflow.rst @@ -78,6 +78,9 @@ slice notation makes this especially convenient:: >>> words ['defenestrate', 'cat', 'window', 'defenestrate'] +With ``for w in words:``, the example would attempt to create an infinite list, +inserting ``defenestrate`` over and over again. + .. _tut-range: diff --git a/Doc/tutorial/inputoutput.rst b/Doc/tutorial/inputoutput.rst index dd9c7cd731..beeaac36b9 100644 --- a/Doc/tutorial/inputoutput.rst +++ b/Doc/tutorial/inputoutput.rst @@ -25,7 +25,8 @@ first way is to do all the string handling yourself; using string slicing and concatenation operations you can create any layout you can imagine. The string type has some methods that perform useful operations for padding strings to a given column width; these will be discussed shortly. The second -way is to use the :meth:`str.format` method. +way is to use :ref:`formatted string literals <f-strings>`, or the +:meth:`str.format` method. The :mod:`string` module contains a :class:`~string.Template` class which offers yet another way to substitute values into strings. diff --git a/Doc/tutorial/interpreter.rst b/Doc/tutorial/interpreter.rst index e966085f93..c89fae36cb 100644 --- a/Doc/tutorial/interpreter.rst +++ b/Doc/tutorial/interpreter.rst @@ -10,13 +10,13 @@ Using the Python Interpreter Invoking the Interpreter ======================== -The Python interpreter is usually installed as :file:`/usr/local/bin/python3.5` +The Python interpreter is usually installed as :file:`/usr/local/bin/python3.6` on those machines where it is available; putting :file:`/usr/local/bin` in your Unix shell's search path makes it possible to start it by typing the command: .. code-block:: text - python3.5 + python3.6 to the shell. [#]_ Since the choice of the directory where the interpreter lives is an installation option, other places are possible; check with your local @@ -24,11 +24,11 @@ Python guru or system administrator. (E.g., :file:`/usr/local/python` is a popular alternative location.) On Windows machines, the Python installation is usually placed in -:file:`C:\\Python35`, though you can change this when you're running the +:file:`C:\\Python36`, though you can change this when you're running the installer. To add this directory to your path, you can type the following command into the command prompt in a DOS box:: - set path=%path%;C:\python35 + set path=%path%;C:\python36 Typing an end-of-file character (:kbd:`Control-D` on Unix, :kbd:`Control-Z` on Windows) at the primary prompt causes the interpreter to exit with a zero exit @@ -96,8 +96,8 @@ with the *secondary prompt*, by default three dots (``...``). The interpreter prints a welcome message stating its version number and a copyright notice before printing the first prompt:: - $ python3.5 - Python 3.5 (default, Sep 16 2015, 09:25:04) + $ python3.6 + Python 3.6 (default, Sep 16 2015, 09:25:04) [GCC 4.8.2] on linux Type "help", "copyright", "credits" or "license" for more information. >>> diff --git a/Doc/tutorial/introduction.rst b/Doc/tutorial/introduction.rst index 214032917b..7e8ee3e5ea 100644 --- a/Doc/tutorial/introduction.rst +++ b/Doc/tutorial/introduction.rst @@ -352,6 +352,9 @@ The built-in function :func:`len` returns the length of a string:: Strings support a large number of methods for basic transformations and searching. + :ref:`f-strings` + String literals that have embedded expressions. + :ref:`formatstrings` Information about string formatting with :meth:`str.format`. diff --git a/Doc/tutorial/stdlib.rst b/Doc/tutorial/stdlib.rst index 52ffdbe063..1dd06c2338 100644 --- a/Doc/tutorial/stdlib.rst +++ b/Doc/tutorial/stdlib.rst @@ -15,7 +15,7 @@ operating system:: >>> import os >>> os.getcwd() # Return the current working directory - 'C:\\Python35' + 'C:\\Python36' >>> os.chdir('/server/accesslogs') # Change current working directory >>> os.system('mkdir today') # Run the command mkdir in the system shell 0 diff --git a/Doc/tutorial/stdlib2.rst b/Doc/tutorial/stdlib2.rst index 3714384eb6..bf4cf87dc3 100644 --- a/Doc/tutorial/stdlib2.rst +++ b/Doc/tutorial/stdlib2.rst @@ -278,7 +278,7 @@ applications include caching objects that are expensive to create:: Traceback (most recent call last): File "<stdin>", line 1, in <module> d['primary'] # entry was automatically removed - File "C:/python35/lib/weakref.py", line 46, in __getitem__ + File "C:/python36/lib/weakref.py", line 46, in __getitem__ o = self.data[key]() KeyError: 'primary' diff --git a/Doc/using/cmdline.rst b/Doc/using/cmdline.rst index ec744a351d..49fe3a01bd 100644 --- a/Doc/using/cmdline.rst +++ b/Doc/using/cmdline.rst @@ -621,6 +621,54 @@ conflict. .. versionadded:: 3.4 +.. envvar:: PYTHONMALLOC + + Set the Python memory allocators and/or install debug hooks. + + Set the family of memory allocators used by Python: + + * ``malloc``: use the :c:func:`malloc` function of the C library + for all domains (:c:data:`PYMEM_DOMAIN_RAW`, :c:data:`PYMEM_DOMAIN_MEM`, + :c:data:`PYMEM_DOMAIN_OBJ`). + * ``pymalloc``: use the :ref:`pymalloc allocator <pymalloc>` for + :c:data:`PYMEM_DOMAIN_MEM` and :c:data:`PYMEM_DOMAIN_OBJ` domains and use + the :c:func:`malloc` function for the :c:data:`PYMEM_DOMAIN_RAW` domain. + + Install debug hooks: + + * ``debug``: install debug hooks on top of the default memory allocator + * ``malloc_debug``: same as ``malloc`` but also install debug hooks + * ``pymalloc_debug``: same as ``pymalloc`` but also install debug hooks + + When Python is compiled in release mode, the default is ``pymalloc``. When + compiled in debug mode, the default is ``pymalloc_debug`` and the debug hooks + are used automatically. + + If Python is configured without ``pymalloc`` support, ``pymalloc`` and + ``pymalloc_debug`` are not available, the default is ``malloc`` in release + mode and ``malloc_debug`` in debug mode. + + See the :c:func:`PyMem_SetupDebugHooks` function for debug hooks on Python + memory allocators. + + .. versionadded:: 3.6 + + +.. envvar:: PYTHONMALLOCSTATS + + If set to a non-empty string, Python will print statistics of the + :ref:`pymalloc memory allocator <pymalloc>` every time a new pymalloc object + arena is created, and on shutdown. + + This variable is ignored if the :envvar:`PYTHONMALLOC` environment variable + is used to force the :c:func:`malloc` allocator of the C library, or if + Python is configured without ``pymalloc`` support. + + .. versionchanged:: 3.6 + This variable can now also be used on Python compiled in release mode. + It now has no effect if set to an empty string. + + Debug-mode variables ~~~~~~~~~~~~~~~~~~~~ @@ -636,9 +684,3 @@ if Python was configured with the ``--with-pydebug`` build option. If set, Python will dump objects and reference counts still alive after shutting down the interpreter. - - -.. envvar:: PYTHONMALLOCSTATS - - If set, Python will print memory allocation statistics every time a new - object arena is created, and on shutdown. diff --git a/Doc/using/mac.rst b/Doc/using/mac.rst index 05c91bba59..8f1ac3f3fd 100644 --- a/Doc/using/mac.rst +++ b/Doc/using/mac.rst @@ -25,7 +25,7 @@ there. What you get after installing is a number of things: -* A :file:`MacPython 3.5` folder in your :file:`Applications` folder. In here +* A :file:`MacPython 3.6` folder in your :file:`Applications` folder. In here you find IDLE, the development environment that is a standard part of official Python distributions; PythonLauncher, which handles double-clicking Python scripts from the Finder; and the "Build Applet" tool, which allows you to @@ -93,7 +93,7 @@ aware of: programs that talk to the Aqua window manager (in other words, anything that has a GUI) need to be run in a special way. Use :program:`pythonw` instead of :program:`python` to start such scripts. -With Python 3.5, you can use either :program:`python` or :program:`pythonw`. +With Python 3.6, you can use either :program:`python` or :program:`pythonw`. Configuration @@ -159,7 +159,7 @@ https://riverbankcomputing.com/software/pyqt/intro. Distributing Python Applications on the Mac =========================================== -The "Build Applet" tool that is placed in the MacPython 3.5 folder is fine for +The "Build Applet" tool that is placed in the MacPython 3.6 folder is fine for packaging small Python scripts on your own machine to run as a standard Mac application. This tool, however, is not robust enough to distribute Python applications to other users. diff --git a/Doc/using/windows.rst b/Doc/using/windows.rst index 7520d60846..2399278752 100644 --- a/Doc/using/windows.rst +++ b/Doc/using/windows.rst @@ -418,6 +418,8 @@ Getting started From the command-line ^^^^^^^^^^^^^^^^^^^^^ +.. versionchanged:: 3.6 + System-wide installations of Python 3.3 and later will put the launcher on your :envvar:`PATH`. The launcher is compatible with all available versions of Python, so it does not matter which version is installed. To check that the @@ -427,25 +429,26 @@ launcher is available, execute the following command in Command Prompt: py -You should find that the latest version of Python 2.x you have installed is +You should find that the latest version of Python you have installed is started - it can be exited as normal, and any additional command-line arguments specified will be sent directly to Python. -If you have multiple versions of Python 2.x installed (e.g., 2.6 and 2.7) you -will have noticed that Python 2.7 was started - to launch Python 2.6, try the +If you have multiple versions of Python installed (e.g., 2.7 and 3.6) you +will have noticed that Python 3.6 was started - to launch Python 2.7, try the command: :: - py -2.6 + py -2.7 -If you have a Python 3.x installed, try the command: +If you want the latest version of Python 2.x you have installed, try the +command: :: - py -3 + py -2 -You should find the latest version of Python 3.x starts. +You should find the latest version of Python 2.x starts. If you see the following error, you do not have the launcher installed: @@ -500,6 +503,11 @@ version qualifier. Assuming you have Python 2.6 installed, try changing the first line to ``#! python2.6`` and you should find the 2.6 version information printed. +Note that unlike interactive use, a bare "python" will use the latest +version of Python 2.x that you have installed. This is for backward +compatibility and for compatibility with Unix, where the command ``python`` +typically refers to Python 2. + From file associations ^^^^^^^^^^^^^^^^^^^^^^ diff --git a/Doc/whatsnew/2.1.rst b/Doc/whatsnew/2.1.rst index e55eaace26..6e192dcd22 100644 --- a/Doc/whatsnew/2.1.rst +++ b/Doc/whatsnew/2.1.rst @@ -367,7 +367,7 @@ dictionary:: This version works for simple things such as integers, but it has a side effect; the ``_cache`` dictionary holds a reference to the return values, so they'll -never be deallocated until the Python process exits and cleans up This isn't +never be deallocated until the Python process exits and cleans up. This isn't very noticeable for integers, but if :func:`f` returns an object, or a data structure that takes up a lot of memory, this can be a problem. diff --git a/Doc/whatsnew/3.6.rst b/Doc/whatsnew/3.6.rst new file mode 100644 index 0000000000..f438f0b44f --- /dev/null +++ b/Doc/whatsnew/3.6.rst @@ -0,0 +1,663 @@ +**************************** + What's New In Python 3.6 +**************************** + +:Release: |release| +:Date: |today| + +.. Rules for maintenance: + + * Anyone can add text to this document. Do not spend very much time + on the wording of your changes, because your text will probably + get rewritten to some degree. + + * The maintainer will go through Misc/NEWS periodically and add + changes; it's therefore more important to add your changes to + Misc/NEWS than to this file. + + * This is not a complete list of every single change; completeness + is the purpose of Misc/NEWS. Some changes I consider too small + or esoteric to include. If such a change is added to the text, + I'll just remove it. (This is another reason you shouldn't spend + too much time on writing your addition.) + + * If you want to draw your new text to the attention of the + maintainer, add 'XXX' to the beginning of the paragraph or + section. + + * It's OK to just add a fragmentary note about a change. For + example: "XXX Describe the transmogrify() function added to the + socket module." The maintainer will research the change and + write the necessary text. + + * You can comment out your additions if you like, but it's not + necessary (especially when a final release is some months away). + + * Credit the author of a patch or bugfix. Just the name is + sufficient; the e-mail address isn't necessary. + + * It's helpful to add the bug/patch number as a comment: + + XXX Describe the transmogrify() function added to the socket + module. + (Contributed by P.Y. Developer in :issue:`12345`.) + + This saves the maintainer the effort of going through the Mercurial log + when researching a change. + +This article explains the new features in Python 3.6, compared to 3.5. + +For full details, see the :source:`Misc/NEWS` file. + +.. note:: + + Prerelease users should be aware that this document is currently in draft + form. It will be updated substantially as Python 3.6 moves towards release, + so it's worth checking back even after reading earlier versions. + + +Summary -- Release highlights +============================= + +.. This section singles out the most important changes in Python 3.6. + Brevity is key. + +New syntax features: + +* PEP 498: :ref:`Formatted string literals <whatsnew-fstrings>` + +Windows improvements: + +* The ``py.exe`` launcher, when used interactively, no longer prefers + Python 2 over Python 3 when the user doesn't specify a version (via + command line arguments or a config file). Handling of shebang lines + remains unchanged - "python" refers to Python 2 in that case. + +.. PEP-sized items next. + +.. _pep-4XX: + +.. PEP 4XX: Virtual Environments +.. ============================= + + +.. (Implemented by Foo Bar.) + +.. .. seealso:: + + :pep:`4XX` - Python Virtual Environments + PEP written by Carl Meyer + + +New Features +============ + +.. _whatsnew-fstrings: + +PEP 498: Formatted string literals +---------------------------------- + +Formatted string literals are a new kind of string literal, prefixed +with ``'f'``. They are similar to the format strings accepted by +:meth:`str.format`. They contain replacement fields surrounded by +curly braces. The replacement fields are expressions, which are +evaluated at run time, and then formatted using the :func:`format` protocol. + + >>> name = "Fred" + >>> f"He said his name is {name}." + 'He said his name is Fred.' + +See :pep:`498` and the main documentation at :ref:`f-strings`. + + +PYTHONMALLOC environment variable +--------------------------------- + +The new :envvar:`PYTHONMALLOC` environment variable allows to set the Python +memory allocators and/or install debug hooks. + +It is now possible to install debug hooks on Python memory allocators on Python +compiled in release mode using ``PYTHONMALLOC=debug``. Effects of debug hooks: + +* Newly allocated memory is filled with the byte ``0xCB`` +* Freed memory is filled with the byte ``0xDB`` +* Detect violations of Python memory allocator API. For example, + :c:func:`PyObject_Free` called on a memory block allocated by + :c:func:`PyMem_Malloc`. +* Detect write before the start of the buffer (buffer underflow) +* Detect write after the end of the buffer (buffer overflow) +* Check that the :term:`GIL <global interpreter lock>` is held when allocator + functions of :c:data:`PYMEM_DOMAIN_OBJ` (ex: :c:func:`PyObject_Malloc`) and + :c:data:`PYMEM_DOMAIN_MEM` (ex: :c:func:`PyMem_Malloc`) domains are called. + +Checking if the GIL is held is also a new feature of Python 3.6. + +See the :c:func:`PyMem_SetupDebugHooks` function for debug hooks on Python +memory allocators. + +It is now also possible to force the usage of the :c:func:`malloc` allocator of +the C library for all Python memory allocations using ``PYTHONMALLOC=malloc``. +It helps to use external memory debuggers like Valgrind on a Python compiled in +release mode. + +On error, the debug hooks on Python memory allocators now use the +:mod:`tracemalloc` module to get the traceback where a memory block was +allocated. + +Example of fatal error on buffer overflow using +``python3.6 -X tracemalloc=5`` (store 5 frames in traces):: + + Debug memory block at address p=0x7fbcd41666f8: API 'o' + 4 bytes originally requested + The 7 pad bytes at p-7 are FORBIDDENBYTE, as expected. + The 8 pad bytes at tail=0x7fbcd41666fc are not all FORBIDDENBYTE (0xfb): + at tail+0: 0x02 *** OUCH + at tail+1: 0xfb + at tail+2: 0xfb + at tail+3: 0xfb + at tail+4: 0xfb + at tail+5: 0xfb + at tail+6: 0xfb + at tail+7: 0xfb + The block was made by call #1233329 to debug malloc/realloc. + Data at p: 1a 2b 30 00 + + Memory block allocated at (most recent call first): + File "test/test_bytes.py", line 323 + File "unittest/case.py", line 600 + File "unittest/case.py", line 648 + File "unittest/suite.py", line 122 + File "unittest/suite.py", line 84 + + Fatal Python error: bad trailing pad byte + + Current thread 0x00007fbcdbd32700 (most recent call first): + File "test/test_bytes.py", line 323 in test_hex + File "unittest/case.py", line 600 in run + File "unittest/case.py", line 648 in __call__ + File "unittest/suite.py", line 122 in run + File "unittest/suite.py", line 84 in __call__ + File "unittest/suite.py", line 122 in run + File "unittest/suite.py", line 84 in __call__ + ... + +(Contributed by Victor Stinner in :issue:`26516` and :issue:`26564`.) + + +Other Language Changes +====================== + +* None yet. + + +New Modules +=========== + +* None yet. + + +Improved Modules +================ + + +asyncio +------- + +Since the :mod:`asyncio` module is :term:`provisional <provisional api>`, +all changes introduced in Python 3.6 have also been backported to Python +3.5.x. + +Notable changes in the :mod:`asyncio` module since Python 3.5.0: + +* The :func:`~asyncio.ensure_future` function and all functions that + use it, such as :meth:`loop.run_until_complete() <asyncio.BaseEventLoop.run_until_complete>`, + now accept all kinds of :term:`awaitable objects <awaitable>`. + (Contributed by Yury Selivanov.) + +* New :func:`~asyncio.run_coroutine_threadsafe` function to submit + coroutines to event loops from other threads. + (Contributed by Vincent Michel.) + +* New :meth:`Transport.is_closing() <asyncio.BaseTransport.is_closing>` + method to check if the transport is closing or closed. + (Contributed by Yury Selivanov.) + +* The :meth:`loop.create_server() <asyncio.BaseEventLoop.create_server>` + method can now accept a list of hosts. + (Contributed by Yann Sionneau.) + +* New :meth:`loop.create_future() <asyncio.BaseEventLoop.create_future>` + method to create Future objects. This allows alternative event + loop implementations, such as + `uvloop <https://github.com/MagicStack/uvloop>`_, to provide a faster + :class:`asyncio.Future` implementation. + (Contributed by Yury Selivanov.) + +* New :meth:`loop.get_exception_handler() <asyncio.BaseEventLoop.get_exception_handler>` + method to get the current exception handler. + (Contributed by Yury Selivanov.) + +* New :func:`~asyncio.timeout` context manager to simplify timeouts + handling code. + (Contributed by Andrew Svetlov.) + +* New :meth:`StreamReader.readuntil() <asyncio.StreamReader.readuntil>` + method to read data from the stream until a separator bytes + sequence appears. + (Contributed by Mark Korenberg.) + +* The :meth:`loop.getaddrinfo() <asyncio.BaseEventLoop.getaddrinfo>` + method is optimized to avoid calling the system ``getaddrinfo`` + function if the address is already resolved. + (Contributed by A. Jesse Jiryu Davis.) + + +contextlib +---------- + +The :class:`contextlib.AbstractContextManager` class has been added to +provide an abstract base class for context managers. It provides a +sensible default implementation for `__enter__()` which returns +``self`` and leaves `__exit__()` an abstract method. A matching +class has been added to the :mod:`typing` module as +:class:`typing.ContextManager`. +(Contributed by Brett Cannon in :issue:`25609`.) + + +datetime +-------- + +The :meth:`datetime.strftime() <datetime.datetime.strftime>` and +:meth:`date.strftime() <datetime.date.strftime>` methods now support ISO 8601 date +directives ``%G``, ``%u`` and ``%V``. +(Contributed by Ashley Anderson in :issue:`12006`.) + + +faulthandler +------------ + +On Windows, the :mod:`faulthandler` module now installs a handler for Windows +exceptions: see :func:`faulthandler.enable`. (Contributed by Victor Stinner in +:issue:`23848`.) + + +os +-- + +A new :meth:`~os.scandir.close` method allows explicitly closing a +:func:`~os.scandir` iterator. The :func:`~os.scandir` iterator now +supports the :term:`context manager` protocol. If a :func:`scandir` +iterator is neither exhausted nor explicitly closed a :exc:`ResourceWarning` +will be emitted in its destructor. +(Contributed by Serhiy Storchaka in :issue:`25994`.) + + +pickle +------ + +Objects that need calling ``__new__`` with keyword arguments can now be pickled +using :ref:`pickle protocols <pickle-protocols>` older than protocol version 4. +Protocol version 4 already supports this case. (Contributed by Serhiy +Storchaka in :issue:`24164`.) + + +readline +-------- + +Added :func:`~readline.set_auto_history` to enable or disable +automatic addition of input to the history list. (Contributed by +Tyler Crompton in :issue:`26870`.) + + +rlcompleter +----------- + +Private and special attribute names now are omitted unless the prefix starts +with underscores. A space or a colon is added after some completed keywords. +(Contributed by Serhiy Storchaka in :issue:`25011` and :issue:`25209`.) + +Names of most attributes listed by :func:`dir` are now completed. +Previously, names of properties and slots which were not yet created on +an instance were excluded. (Contributed by Martin Panter in :issue:`25590`.) + + +site +---- + +When specifying paths to add to :attr:`sys.path` in a `.pth` file, +you may now specify file paths on top of directories (e.g. zip files). +(Contributed by Wolfgang Langner in :issue:`26587`). + + +socketserver +------------ + +Servers based on the :mod:`socketserver` module, including those +defined in :mod:`http.server`, :mod:`xmlrpc.server` and +:mod:`wsgiref.simple_server`, now support the :term:`context manager` +protocol. +(Contributed by Aviv Palivoda in :issue:`26404`.) + + +subprocess +---------- + +:class:`subprocess.Popen` destructor now emits a :exc:`ResourceWarning` warning +if the child process is still running. Use the context manager protocol (``with +proc: ...``) or call explicitly the :meth:`~subprocess.Popen.wait` method to +read the exit status of the child process (Contributed by Victor Stinner in +:issue:`26741`). + + +telnetlib +--------- + +:class:`~telnetlib.Telnet` is now a context manager (contributed by +Stéphane Wirtel in :issue:`25485`). + + +typing +------ + +The :class:`typing.ContextManager` class has been added for +representing :class:`contextlib.AbstractContextManager`. +(Contributed by Brett Cannon in :issue:`25609`.) + + +unittest.mock +------------- + +The :class:`~unittest.mock.Mock` class has the following improvements: + +* Two new methods, :meth:`Mock.assert_called() + <unittest.mock.Mock.assert_called>` and :meth:`Mock.assert_called_once() + <unittest.mock.Mock.assert_called_once>` to check if the mock object + was called. + (Contributed by Amit Saha in :issue:`26323`.) + + +urllib.robotparser +------------------ + +:class:`~urllib.robotparser.RobotFileParser` now supports the ``Crawl-delay`` and +``Request-rate`` extensions. +(Contributed by Nikolay Bogoychev in :issue:`16099`.) + + +warnings +-------- + +A new optional *source* parameter has been added to the +:func:`warnings.warn_explicit` function: the destroyed object which emitted a +:exc:`ResourceWarning`. A *source* attribute has also been added to +:class:`warnings.WarningMessage` (contributed by Victor Stinner in +:issue:`26568` and :issue:`26567`). + +When a :exc:`ResourceWarning` warning is logged, the :mod:`tracemalloc` is now +used to try to retrieve the traceback where the detroyed object was allocated. + +Example with the script ``example.py``:: + + import warnings + + def func(): + return open(__file__) + + f = func() + f = None + +Output of the command ``python3.6 -Wd -X tracemalloc=5 example.py``:: + + example.py:7: ResourceWarning: unclosed file <_io.TextIOWrapper name='example.py' mode='r' encoding='UTF-8'> + f = None + Object allocated at (most recent call first): + File "example.py", lineno 4 + return open(__file__) + File "example.py", lineno 6 + f = func() + +The "Object allocated at" traceback is new and only displayed if +:mod:`tracemalloc` is tracing Python memory allocations and if the +:mod:`warnings` was already imported. + + +winreg +------ + +Added the 64-bit integer type :data:`REG_QWORD <winreg.REG_QWORD>`. +(Contributed by Clement Rouault in :issue:`23026`.) + + +zipfile +------- + +A new :meth:`ZipInfo.from_file() <zipfile.ZipInfo.from_file>` class method +allows making a :class:`~zipfile.ZipInfo` instance from a filesystem file. +A new :meth:`ZipInfo.is_dir() <zipfile.ZipInfo.is_dir>` method can be used +to check if the :class:`~zipfile.ZipInfo` instance represents a directory. +(Contributed by Thomas Kluyver in :issue:`26039`.) + +The :meth:`ZipFile.open() <zipfile.ZipFile.open>` method can now be used to +write data into a ZIP file, as well as for extracting data. +(Contributed by Thomas Kluyver in :issue:`26039`.) + + +zlib +---- + +The :func:`~zlib.compress` function now accepts keyword arguments. +(Contributed by Aviv Palivoda in :issue:`26243`.) + + +fileinput +--------- + +:func:`~fileinput.hook_encoded` now supports the *errors* argument. +(Contributed by Joseph Hackman in :issue:`25788`.) + + +Optimizations +============= + +* The ASCII decoder is now up to 60 times as fast for error handlers + ``surrogateescape``, ``ignore`` and ``replace`` (Contributed + by Victor Stinner in :issue:`24870`). + +* The ASCII and the Latin1 encoders are now up to 3 times as fast for the + error handler ``surrogateescape`` (Contributed by Victor Stinner in :issue:`25227`). + +* The UTF-8 encoder is now up to 75 times as fast for error handlers + ``ignore``, ``replace``, ``surrogateescape``, ``surrogatepass`` (Contributed + by Victor Stinner in :issue:`25267`). + +* The UTF-8 decoder is now up to 15 times as fast for error handlers + ``ignore``, ``replace`` and ``surrogateescape`` (Contributed + by Victor Stinner in :issue:`25301`). + +* ``bytes % args`` is now up to 2 times faster. (Contributed by Victor Stinner + in :issue:`25349`). + +* ``bytearray % args`` is now between 2.5 and 5 times faster. (Contributed by + Victor Stinner in :issue:`25399`). + +* Optimize :meth:`bytes.fromhex` and :meth:`bytearray.fromhex`: they are now + between 2x and 3.5x faster. (Contributed by Victor Stinner in :issue:`25401`). + +* Optimize ``bytes.replace(b'', b'.')`` and ``bytearray.replace(b'', b'.')``: + up to 80% faster. (Contributed by Josh Snider in :issue:`26574`). + +* Allocator functions of the :c:func:`PyMem_Malloc` domain + (:c:data:`PYMEM_DOMAIN_MEM`) now use the :ref:`pymalloc memory allocator + <pymalloc>` instead of :c:func:`malloc` function of the C library. The + pymalloc allocator is optimized for objects smaller or equal to 512 bytes + with a short lifetime, and use :c:func:`malloc` for larger memory blocks. + (Contributed by Victor Stinner in :issue:`26249`). + +* :func:`pickle.load` and :func:`pickle.loads` are now up to 10% faster when + deserializing many small objects (Contributed by Victor Stinner in + :issue:`27056`). + +Build and C API Changes +======================= + +* New :c:func:`Py_FinalizeEx` API which indicates if flushing buffered data + failed (:issue:`5319`). + + +Deprecated +========== + +New Keywords +------------ + +``async`` and ``await`` are not recommended to be used as variable, class, +function or module names. Introduced by :pep:`492` in Python 3.5, they will +become proper keywords in Python 3.7. + + +Deprecated Python modules, functions and methods +------------------------------------------------ + +* :meth:`importlib.machinery.SourceFileLoader.load_module` and + :meth:`importlib.machinery.SourcelessFileLoader.load_module` are now + deprecated. They were the only remaining implementations of + :meth:`importlib.abc.Loader.load_module` in :mod:`importlib` that had not + been deprecated in previous versions of Python in favour of + :meth:`importlib.abc.Loader.exec_module`. + + +Deprecated functions and types of the C API +------------------------------------------- + +* None yet. + + +Deprecated features +------------------- + +* The ``pyvenv`` script has been deprecated in favour of ``python3 -m venv``. + This prevents confusion as to what Python interpreter ``pyvenv`` is + connected to and thus what Python interpreter will be used by the virtual + environment. (Contributed by Brett Cannon in :issue:`25154`.) + +* When performing a relative import, falling back on ``__name__`` and + ``__path__`` from the calling module when ``__spec__`` or + ``__package__`` are not defined now raises an :exc:`ImportWarning`. + (Contributed by Rose Ames in :issue:`25791`.) + + +Deprecated Python behavior +-------------------------- + +* Raising the :exc:`StopIteration` exception inside a generator will now generate a + :exc:`DeprecationWarning`, and will trigger a :exc:`RuntimeError` in Python 3.7. + See :ref:`whatsnew-pep-479` for details. + + +Removed +======= + +API and Feature Removals +------------------------ + +* ``inspect.getmoduleinfo()`` was removed (was deprecated since CPython 3.3). + :func:`inspect.getmodulename` should be used for obtaining the module + name for a given path. + +* ``traceback.Ignore`` class and ``traceback.usage``, ``traceback.modname``, + ``traceback.fullmodname``, ``traceback.find_lines_from_code``, + ``traceback.find_lines``, ``traceback.find_strings``, + ``traceback.find_executable_lines`` methods were removed from the + :mod:`traceback` module. They were undocumented methods deprecated since + Python 3.2 and equivalent functionality is available from private methods. + +* The ``tk_menuBar()`` and ``tk_bindForTraversal()`` dummy methods in + :mod:`tkinter` widget classes were removed (corresponding Tk commands + were obsolete since Tk 4.0). + + +Porting to Python 3.6 +===================== + +This section lists previously described changes and other bugfixes +that may require changes to your code. + +Changes in the Python API +------------------------- + +* The format of the ``co_lnotab`` attribute of code objects changed to support + negative line number delta. By default, Python does not emit bytecode with + negative line number delta. Functions using ``frame.f_lineno``, + ``PyFrame_GetLineNumber()`` or ``PyCode_Addr2Line()`` are not affected. + Functions decoding directly ``co_lnotab`` should be updated to use a signed + 8-bit integer type for the line number delta, but it's only required to + support applications using negative line number delta. See + ``Objects/lnotab_notes.txt`` for the ``co_lnotab`` format and how to decode + it, and see the :pep:`511` for the rationale. + +* The functions in the :mod:`compileall` module now return booleans instead + of ``1`` or ``0`` to represent success or failure, respectively. Thanks to + booleans being a subclass of integers, this should only be an issue if you + were doing identity checks for ``1`` or ``0``. See :issue:`25768`. + +* Reading the :attr:`~urllib.parse.SplitResult.port` attribute of + :func:`urllib.parse.urlsplit` and :func:`~urllib.parse.urlparse` results + now raises :exc:`ValueError` for out-of-range values, rather than + returning :const:`None`. See :issue:`20059`. + +* The :mod:`imp` module now raises a :exc:`DeprecationWarning` instead of + :exc:`PendingDeprecationWarning`. + +* The following modules have had missing APIs added to their :attr:`__all__` + attributes to match the documented APIs: + :mod:`calendar`, :mod:`cgi`, :mod:`csv`, + :mod:`~xml.etree.ElementTree`, :mod:`enum`, + :mod:`fileinput`, :mod:`ftplib`, :mod:`logging`, :mod:`mailbox`, + :mod:`mimetypes`, :mod:`optparse`, :mod:`plistlib`, :mod:`smtpd`, + :mod:`subprocess`, :mod:`tarfile`, :mod:`threading` and + :mod:`wave`. This means they will export new symbols when ``import *`` + is used. See :issue:`23883`. + +* When performing a relative import, if ``__package__`` does not compare equal + to ``__spec__.parent`` then :exc:`ImportWarning` is raised. + (Contributed by Brett Cannon in :issue:`25791`.) + +* When a relative import is performed and no parent package is known, then + :exc:`ImportError` will be raised. Previously, :exc:`SystemError` could be + raised. (Contributed by Brett Cannon in :issue:`18018`.) + +* Servers based on the :mod:`socketserver` module, including those + defined in :mod:`http.server`, :mod:`xmlrpc.server` and + :mod:`wsgiref.simple_server`, now only catch exceptions derived + from :exc:`Exception`. Therefore if a request handler raises + an exception like :exc:`SystemExit` or :exc:`KeyboardInterrupt`, + :meth:`~socketserver.BaseServer.handle_error` is no longer called, and + the exception will stop a single-threaded server. (Contributed by + Martin Panter in :issue:`23430`.) + +* :func:`spwd.getspnam` now raises a :exc:`PermissionError` instead of + :exc:`KeyError` if the user doesn't have privileges. + +* The :meth:`socket.socket.close` method now raises an exception if + an error (e.g. EBADF) was reported by the underlying system call. + See :issue:`26685`. + +* The *decode_data* argument for :class:`smtpd.SMTPChannel` and + :class:`smtpd.SMTPServer` constructors is now ``False`` by default. + This means that the argument passed to + :meth:`~smtpd.SMTPServer.process_message` is now a bytes object by + default, and ``process_message()`` will be passed keyword arguments. + Code that has already been updated in accordance with the deprecation + warning generated by 3.5 will not be affected. + +Changes in the C API +-------------------- + +* :c:func:`PyMem_Malloc` allocator family now uses the :ref:`pymalloc allocator + <pymalloc>` rather than system :c:func:`malloc`. Applications calling + :c:func:`PyMem_Malloc` without holding the GIL can now crash. Set the + :envvar:`PYTHONMALLOC` environment variable to ``debug`` to validate the + usage of memory allocators in your application. See :issue:`26249`. + +* :c:func:`Py_Exit` (and the main interpreter) now override the exit status + with 120 if flushing buffered data failed. See :issue:`5319`. diff --git a/Doc/whatsnew/index.rst b/Doc/whatsnew/index.rst index edb55022bd..7c9252401e 100644 --- a/Doc/whatsnew/index.rst +++ b/Doc/whatsnew/index.rst @@ -11,6 +11,7 @@ anyone wishing to stay up-to-date after a new release. .. toctree:: :maxdepth: 2 + 3.6.rst 3.5.rst 3.4.rst 3.3.rst |