diff options
Diffstat (limited to 'Lib/inspect.py')
| -rw-r--r-- | Lib/inspect.py | 346 |
1 files changed, 283 insertions, 63 deletions
diff --git a/Lib/inspect.py b/Lib/inspect.py index 9337bd590b..dc94e44b29 100644 --- a/Lib/inspect.py +++ b/Lib/inspect.py @@ -31,7 +31,7 @@ Here are some of the useful functions provided by this module: __author__ = ('Ka-Ping Yee <ping@lfw.org>', 'Yury Selivanov <yselivanov@sprymix.com>') -import imp +import ast import importlib.machinery import itertools import linecache @@ -268,21 +268,40 @@ def getmembers(object, predicate=None): else: mro = () results = [] - for key in dir(object): - # First try to get the value via __dict__. Some descriptors don't - # like calling their __get__ (see bug #1785). - for base in mro: - if key in base.__dict__: - value = base.__dict__[key] - break - else: - try: - value = getattr(object, key) - except AttributeError: + processed = set() + names = dir(object) + # :dd any DynamicClassAttributes to the list of names if object is a class; + # this may result in duplicate entries if, for example, a virtual + # attribute with the same name as a DynamicClassAttribute exists + try: + for base in object.__bases__: + for k, v in base.__dict__.items(): + if isinstance(v, types.DynamicClassAttribute): + names.append(k) + except AttributeError: + pass + for key in names: + # First try to get the value via getattr. Some descriptors don't + # like calling their __get__ (see bug #1785), so fall back to + # looking in the __dict__. + try: + value = getattr(object, key) + # handle the duplicate key + if key in processed: + raise AttributeError + except AttributeError: + for base in mro: + if key in base.__dict__: + value = base.__dict__[key] + break + else: + # could be a (currently) missing slot member, or a buggy + # __dir__; discard and move on continue if not predicate or predicate(value): results.append((key, value)) - results.sort() + processed.add(key) + results.sort(key=lambda pair: pair[0]) return results Attribute = namedtuple('Attribute', 'name kind defining_class object') @@ -299,60 +318,106 @@ def classify_class_attrs(cls): 'class method' created via classmethod() 'static method' created via staticmethod() 'property' created via property() - 'method' any other flavor of method + 'method' any other flavor of method or descriptor 'data' not a method 2. The class which defined this attribute (a class). - 3. The object as obtained directly from the defining class's - __dict__, not via getattr. This is especially important for - data attributes: C.data is just a data object, but - C.__dict__['data'] may be a data descriptor with additional - info, like a __doc__ string. + 3. The object as obtained by calling getattr; if this fails, or if the + resulting object does not live anywhere in the class' mro (including + metaclasses) then the object is looked up in the defining class's + dict (found by walking the mro). + + If one of the items in dir(cls) is stored in the metaclass it will now + be discovered and not have None be listed as the class in which it was + defined. Any items whose home class cannot be discovered are skipped. """ mro = getmro(cls) + metamro = getmro(type(cls)) # for attributes stored in the metaclass + metamro = tuple([cls for cls in metamro if cls not in (type, object)]) + class_bases = (cls,) + mro + all_bases = class_bases + metamro names = dir(cls) + # :dd any DynamicClassAttributes to the list of names; + # this may result in duplicate entries if, for example, a virtual + # attribute with the same name as a DynamicClassAttribute exists. + for base in mro: + for k, v in base.__dict__.items(): + if isinstance(v, types.DynamicClassAttribute): + names.append(k) result = [] + processed = set() + for name in names: # Get the object associated with the name, and where it was defined. + # Normal objects will be looked up with both getattr and directly in + # its class' dict (in case getattr fails [bug #1785], and also to look + # for a docstring). + # For DynamicClassAttributes on the second pass we only look in the + # class's dict. + # # Getting an obj from the __dict__ sometimes reveals more than # using getattr. Static and class methods are dramatic examples. - # Furthermore, some objects may raise an Exception when fetched with - # getattr(). This is the case with some descriptors (bug #1785). - # Thus, we only use getattr() as a last resort. homecls = None - for base in (cls,) + mro: + get_obj = None + dict_obj = None + if name not in processed: + try: + if name == '__dict__': + raise Exception("__dict__ is special, don't want the proxy") + get_obj = getattr(cls, name) + except Exception as exc: + pass + else: + homecls = getattr(get_obj, "__objclass__", homecls) + if homecls not in class_bases: + # if the resulting object does not live somewhere in the + # mro, drop it and search the mro manually + homecls = None + last_cls = None + # first look in the classes + for srch_cls in class_bases: + srch_obj = getattr(srch_cls, name, None) + if srch_obj == get_obj: + last_cls = srch_cls + # then check the metaclasses + for srch_cls in metamro: + try: + srch_obj = srch_cls.__getattr__(cls, name) + except AttributeError: + continue + if srch_obj == get_obj: + last_cls = srch_cls + if last_cls is not None: + homecls = last_cls + for base in all_bases: if name in base.__dict__: - obj = base.__dict__[name] - homecls = base + dict_obj = base.__dict__[name] + if homecls not in metamro: + homecls = base break - else: - obj = getattr(cls, name) - homecls = getattr(obj, "__objclass__", homecls) - - # Classify the object. - if isinstance(obj, staticmethod): + if homecls is None: + # unable to locate the attribute anywhere, most likely due to + # buggy custom __dir__; discard and move on + continue + obj = get_obj or dict_obj + # Classify the object or its descriptor. + if isinstance(dict_obj, staticmethod): kind = "static method" - elif isinstance(obj, classmethod): + obj = dict_obj + elif isinstance(dict_obj, classmethod): kind = "class method" - elif isinstance(obj, property): + obj = dict_obj + elif isinstance(dict_obj, property): kind = "property" - elif ismethoddescriptor(obj): + obj = dict_obj + elif isfunction(obj) or ismethoddescriptor(obj): kind = "method" - elif isdatadescriptor(obj): - kind = "data" else: - obj_via_getattr = getattr(cls, name) - if (isfunction(obj_via_getattr) or - ismethoddescriptor(obj_via_getattr)): - kind = "method" - else: - kind = "data" - obj = obj_via_getattr - + kind = "data" result.append(Attribute(name, kind, homecls, obj)) - + processed.add(name) return result # ----------------------------------------------------------- class helpers @@ -361,6 +426,40 @@ def getmro(cls): "Return tuple of base classes (including cls) in method resolution order." return cls.__mro__ +# -------------------------------------------------------- function helpers + +def unwrap(func, *, stop=None): + """Get the object wrapped by *func*. + + Follows the chain of :attr:`__wrapped__` attributes returning the last + object in the chain. + + *stop* is an optional callback accepting an object in the wrapper chain + as its sole argument that allows the unwrapping to be terminated early if + the callback returns a true value. If the callback never returns a true + value, the last object in the chain is returned as usual. For example, + :func:`signature` uses this to stop unwrapping if any object in the + chain has a ``__signature__`` attribute defined. + + :exc:`ValueError` is raised if a cycle is encountered. + + """ + if stop is None: + def _is_wrapper(f): + return hasattr(f, '__wrapped__') + else: + def _is_wrapper(f): + return hasattr(f, '__wrapped__') and not stop(f) + f = func # remember the original func for error reporting + memo = {id(f)} # Memoise by id to tolerate non-hashable objects + while _is_wrapper(func): + func = func.__wrapped__ + id_func = id(func) + if id_func in memo: + raise ValueError('wrapper loop when unwrapping {!r}'.format(f)) + memo.add(id_func) + return func + # -------------------------------------------------- source code extraction def indentsize(line): """Return the indent size, in spaces, at the start of a line of text.""" @@ -440,6 +539,9 @@ def getmoduleinfo(path): """Get the module name, suffix, mode, and module type for a given file.""" warnings.warn('inspect.getmoduleinfo() is deprecated', DeprecationWarning, 2) + with warnings.catch_warnings(): + warnings.simplefilter('ignore', PendingDeprecationWarning) + import imp filename = os.path.basename(path) suffixes = [(-len(suffix), suffix, mode, mtype) for suffix, mode, mtype in imp.get_suffixes()] @@ -476,7 +578,7 @@ def getsourcefile(object): if os.path.exists(filename): return filename # only return a non-existent filename if the module has a PEP 302 loader - if hasattr(getmodule(object, filename), '__loader__'): + if getattr(getmodule(object, filename), '__loader__', None) is not None: return filename # or it is in the linecache if filename in linecache.cache: @@ -545,13 +647,13 @@ def findsource(object): The argument may be a module, class, method, function, traceback, frame, or code object. The source code is returned as a list of all the lines - in the file and the line number indexes a line in that list. An IOError + in the file and the line number indexes a line in that list. An OSError is raised if the source code cannot be retrieved.""" file = getfile(object) sourcefile = getsourcefile(object) if not sourcefile and file[:1] + file[-1:] != '<>': - raise IOError('source code not available') + raise OSError('source code not available') file = sourcefile if sourcefile else file module = getmodule(object, file) @@ -560,7 +662,7 @@ def findsource(object): else: lines = linecache.getlines(file) if not lines: - raise IOError('could not get source code') + raise OSError('could not get source code') if ismodule(object): return lines, 0 @@ -586,7 +688,7 @@ def findsource(object): candidates.sort() return lines, candidates[0][1] else: - raise IOError('could not find class definition') + raise OSError('could not find class definition') if ismethod(object): object = object.__func__ @@ -598,14 +700,14 @@ def findsource(object): object = object.f_code if iscode(object): if not hasattr(object, 'co_firstlineno'): - raise IOError('could not find function definition') + raise OSError('could not find function definition') lnum = object.co_firstlineno - 1 pat = re.compile(r'^(\s*def\s)|(.*(?<!\w)lambda(:|\s))|^(\s*@)') while lnum > 0: if pat.match(lines[lnum]): break lnum = lnum - 1 return lines, lnum - raise IOError('could not find code object') + raise OSError('could not find code object') def getcomments(object): """Get lines of comments immediately preceding an object's source code. @@ -614,7 +716,7 @@ def getcomments(object): """ try: lines, lnum = findsource(object) - except (IOError, TypeError): + except (OSError, TypeError): return None if ismodule(object): @@ -710,7 +812,7 @@ def getsourcelines(object): The argument may be a module, class, method, function, traceback, frame, or code object. The source code is returned as a list of the lines corresponding to the object and the line number indicates where in the - original source file the first line of code was found. An IOError is + original source file the first line of code was found. An OSError is raised if the source code cannot be retrieved.""" lines, lnum = findsource(object) @@ -722,7 +824,7 @@ def getsource(object): The argument may be a module, class, method, function, traceback, frame, or code object. The source code is returned as a single string. An - IOError is raised if the source code cannot be retrieved.""" + OSError is raised if the source code cannot be retrieved.""" lines, lnum = getsourcelines(object) return ''.join(lines) @@ -1123,7 +1225,7 @@ def getframeinfo(frame, context=1): start = lineno - 1 - context//2 try: lines, lnum = findsource(frame) - except IOError: + except OSError: lines = index = None else: start = max(start, 1) @@ -1345,6 +1447,9 @@ def signature(obj): sig = signature(obj.__func__) return sig.replace(parameters=tuple(sig.parameters.values())[1:]) + # Was this function wrapped by a decorator? + obj = unwrap(obj, stop=(lambda f: hasattr(f, "__signature__"))) + try: sig = obj.__signature__ except AttributeError: @@ -1353,17 +1458,13 @@ def signature(obj): if sig is not None: return sig - try: - # Was this function wrapped by a decorator? - wrapped = obj.__wrapped__ - except AttributeError: - pass - else: - return signature(wrapped) if isinstance(obj, types.FunctionType): return Signature.from_function(obj) + if isinstance(obj, types.BuiltinFunctionType): + return Signature.from_builtin(obj) + if isinstance(obj, functools.partial): sig = signature(obj.func) @@ -1845,6 +1946,64 @@ class Signature: return_annotation=annotations.get('return', _empty), __validate_parameters__=False) + @classmethod + def from_builtin(cls, func): + s = getattr(func, "__text_signature__", None) + if not s: + return None + + if s.endswith("/)"): + kind = Parameter.POSITIONAL_ONLY + s = s[:-2] + ')' + else: + kind = Parameter.POSITIONAL_OR_KEYWORD + + s = "def foo" + s + ": pass" + + try: + module = ast.parse(s) + except SyntaxError: + return None + if not isinstance(module, ast.Module): + return None + + # ast.FunctionDef + f = module.body[0] + + parameters = [] + empty = Parameter.empty + + def p(name_node, default_node, default=empty): + name = name_node.arg + + if isinstance(default_node, ast.Num): + default = default.n + elif isinstance(default_node, ast.NameConstant): + default = default_node.value + parameters.append(Parameter(name, kind, default=default, annotation=empty)) + + # non-keyword-only parameters + for name, default in reversed(list(itertools.zip_longest(reversed(f.args.args), reversed(f.args.defaults), fillvalue=None))): + p(name, default) + + # *args + if f.args.vararg: + kind = Parameter.VAR_POSITIONAL + p(f.args.vararg, empty) + + # keyword-only arguments + kind = Parameter.KEYWORD_ONLY + for name, default in zip(f.args.kwonlyargs, f.args.kw_defaults): + p(name, default) + + # **kwargs + if f.args.kwarg: + kind = Parameter.VAR_KEYWORD + p(f.args.kwarg, empty) + + return cls(parameters, return_annotation=cls.empty) + + @property def parameters(self): return self._parameters @@ -2072,3 +2231,64 @@ class Signature: rendered += ' -> {}'.format(anno) return rendered + +def _main(): + """ Logic for inspecting an object given at command line """ + import argparse + import importlib + + parser = argparse.ArgumentParser() + parser.add_argument( + 'object', + help="The object to be analysed. " + "It supports the 'module:qualname' syntax") + parser.add_argument( + '-d', '--details', action='store_true', + help='Display info about the module rather than its source code') + + args = parser.parse_args() + + target = args.object + mod_name, has_attrs, attrs = target.partition(":") + try: + obj = module = importlib.import_module(mod_name) + except Exception as exc: + msg = "Failed to import {} ({}: {})".format(mod_name, + type(exc).__name__, + exc) + print(msg, file=sys.stderr) + exit(2) + + if has_attrs: + parts = attrs.split(".") + obj = module + for part in parts: + obj = getattr(obj, part) + + if module.__name__ in sys.builtin_module_names: + print("Can't get info for builtin modules.", file=sys.stderr) + exit(1) + + if args.details: + print('Target: {}'.format(target)) + print('Origin: {}'.format(getsourcefile(module))) + print('Cached: {}'.format(module.__cached__)) + if obj is module: + print('Loader: {}'.format(repr(module.__loader__))) + if hasattr(module, '__path__'): + print('Submodule search path: {}'.format(module.__path__)) + else: + try: + __, lineno = findsource(obj) + except Exception: + pass + else: + print('Line: {}'.format(lineno)) + + print('\n') + else: + print(getsource(obj)) + + +if __name__ == "__main__": + _main() |