Issue #24257: Fixed incorrect uses of PyObject_IsInstance().

Fixed segmentation fault in sqlite3.Row constructor with faked cursor type.
Fixed system error in the comparison of faked types.SimpleNamespace.

1 files changed, 196 insertions, 23 deletions

diff --git a/Objects/genobject.c b/Objects/genobject.c
index 67e6ef9e00..555e4fd76e 100644
--- a/Objects/genobject.c
+++ b/Objects/genobject.c
@@ -12,6 +12,8 @@ gen_traverse(PyGenObject *gen, visitproc visit, void *arg)
 {
     Py_VISIT((PyObject *)gen->gi_frame);
     Py_VISIT(gen->gi_code);
+    Py_VISIT(gen->gi_name);
+    Py_VISIT(gen->gi_qualname);
     return 0;
 }
 
@@ -22,6 +24,19 @@ _PyGen_Finalize(PyObject *self)
     PyObject *res;
     PyObject *error_type, *error_value, *error_traceback;
 
+    /* If `gen` is a coroutine, and if it was never awaited on,
+       issue a RuntimeWarning. */
+    if (gen->gi_code != NULL
+            && ((PyCodeObject *)gen->gi_code)->co_flags & (CO_COROUTINE
+                                                       | CO_ITERABLE_COROUTINE)
+            && gen->gi_frame != NULL
+            && gen->gi_frame->f_lasti == -1
+            && !PyErr_Occurred()
+            && PyErr_WarnFormat(PyExc_RuntimeWarning, 1,
+                                "coroutine '%.50S' was never awaited",
+                                gen->gi_qualname))
+        return;
+
     if (gen->gi_frame == NULL || gen->gi_frame->f_stacktop == NULL)
         /* Generator isn't paused, so no need to close */
         return;
@@ -58,6 +73,8 @@ gen_dealloc(PyGenObject *gen)
     _PyObject_GC_UNTRACK(self);
     Py_CLEAR(gen->gi_frame);
     Py_CLEAR(gen->gi_code);
+    Py_CLEAR(gen->gi_name);
+    Py_CLEAR(gen->gi_qualname);
     PyObject_GC_Del(gen);
 }
 
@@ -126,6 +143,31 @@ gen_send_ex(PyGenObject *gen, PyObject *arg, int exc)
         }
         Py_CLEAR(result);
     }
+    else if (!result) {
+        /* Check for __future__ generator_stop and conditionally turn
+         * a leaking StopIteration into RuntimeError (with its cause
+         * set appropriately). */
+        if ((((PyCodeObject *)gen->gi_code)->co_flags &
+              (CO_FUTURE_GENERATOR_STOP | CO_COROUTINE | CO_ITERABLE_COROUTINE))
+            && PyErr_ExceptionMatches(PyExc_StopIteration))
+        {
+            PyObject *exc, *val, *val2, *tb;
+            PyErr_Fetch(&exc, &val, &tb);
+            PyErr_NormalizeException(&exc, &val, &tb);
+            if (tb != NULL)
+                PyException_SetTraceback(val, tb);
+            Py_DECREF(exc);
+            Py_XDECREF(tb);
+            PyErr_SetString(PyExc_RuntimeError,
+                "generator raised StopIteration");
+            PyErr_Fetch(&exc, &val2, &tb);
+            PyErr_NormalizeException(&exc, &val2, &tb);
+            Py_INCREF(val);
+            PyException_SetCause(val2, val);
+            PyException_SetContext(val2, val);
+            PyErr_Restore(exc, val2, tb);
+        }
+    }
 
     if (!result || f->f_stacktop == NULL) {
         /* generator can't be rerun, so release the frame */
@@ -373,11 +415,13 @@ failed_throw:
 static PyObject *
 gen_iternext(PyGenObject *gen)
 {
-    PyObject *val = NULL;
-    PyObject *ret;
-    ret = gen_send_ex(gen, val, 0);
-    Py_XDECREF(val);
-    return ret;
+    if (((PyCodeObject*)gen->gi_code)->co_flags & CO_COROUTINE) {
+        PyErr_SetString(PyExc_TypeError,
+                        "coroutine-objects do not support iteration");
+        return NULL;
+    }
+
+    return gen_send_ex(gen, NULL, 0);
 }
 
 /*
@@ -433,34 +477,93 @@ _PyGen_FetchStopIterationValue(PyObject **pvalue) {
 static PyObject *
 gen_repr(PyGenObject *gen)
 {
-    return PyUnicode_FromFormat("<generator object %S at %p>",
-                                ((PyCodeObject *)gen->gi_code)->co_name,
-                                gen);
+    if (PyGen_CheckCoroutineExact(gen)) {
+        return PyUnicode_FromFormat("<coroutine object %S at %p>",
+                                    gen->gi_qualname, gen);
+    }
+    else {
+        return PyUnicode_FromFormat("<generator object %S at %p>",
+                                    gen->gi_qualname, gen);
+    }
 }
 
+static PyObject *
+gen_get_name(PyGenObject *op)
+{
+    Py_INCREF(op->gi_name);
+    return op->gi_name;
+}
+
+static int
+gen_set_name(PyGenObject *op, PyObject *value)
+{
+    PyObject *tmp;
+
+    /* Not legal to del gen.gi_name or to set it to anything
+     * other than a string object. */
+    if (value == NULL || !PyUnicode_Check(value)) {
+        PyErr_SetString(PyExc_TypeError,
+                        "__name__ must be set to a string object");
+        return -1;
+    }
+    tmp = op->gi_name;
+    Py_INCREF(value);
+    op->gi_name = value;
+    Py_DECREF(tmp);
+    return 0;
+}
 
 static PyObject *
-gen_get_name(PyGenObject *gen)
+gen_get_qualname(PyGenObject *op)
 {
-    PyObject *name = ((PyCodeObject *)gen->gi_code)->co_name;
-    Py_INCREF(name);
-    return name;
+    Py_INCREF(op->gi_qualname);
+    return op->gi_qualname;
 }
 
+static PyObject *
+gen_get_iter(PyGenObject *gen)
+{
+    if (((PyCodeObject*)gen->gi_code)->co_flags & CO_COROUTINE) {
+        PyErr_SetString(PyExc_TypeError,
+                        "coroutine-objects do not support iteration");
+        return NULL;
+    }
+
+    Py_INCREF(gen);
+    return (PyObject *)gen;
+}
 
-PyDoc_STRVAR(gen__name__doc__,
-"Return the name of the generator's associated code object.");
+static int
+gen_set_qualname(PyGenObject *op, PyObject *value)
+{
+    PyObject *tmp;
+
+    /* Not legal to del gen.__qualname__ or to set it to anything
+     * other than a string object. */
+    if (value == NULL || !PyUnicode_Check(value)) {
+        PyErr_SetString(PyExc_TypeError,
+                        "__qualname__ must be set to a string object");
+        return -1;
+    }
+    tmp = op->gi_qualname;
+    Py_INCREF(value);
+    op->gi_qualname = value;
+    Py_DECREF(tmp);
+    return 0;
+}
 
 static PyGetSetDef gen_getsetlist[] = {
-    {"__name__", (getter)gen_get_name, NULL, gen__name__doc__},
-    {NULL}
+    {"__name__", (getter)gen_get_name, (setter)gen_set_name,
+     PyDoc_STR("name of the generator")},
+    {"__qualname__", (getter)gen_get_qualname, (setter)gen_set_qualname,
+     PyDoc_STR("qualified name of the generator")},
+    {NULL} /* Sentinel */
 };
 
-
 static PyMemberDef gen_memberlist[] = {
-    {"gi_frame",        T_OBJECT, offsetof(PyGenObject, gi_frame),      READONLY},
-    {"gi_running",      T_BOOL,    offsetof(PyGenObject, gi_running),    READONLY},
-    {"gi_code",     T_OBJECT, offsetof(PyGenObject, gi_code),  READONLY},
+    {"gi_frame",     T_OBJECT, offsetof(PyGenObject, gi_frame),    READONLY},
+    {"gi_running",   T_BOOL,   offsetof(PyGenObject, gi_running),  READONLY},
+    {"gi_code",      T_OBJECT, offsetof(PyGenObject, gi_code),     READONLY},
     {NULL}      /* Sentinel */
 };
 
@@ -481,7 +584,7 @@ PyTypeObject PyGen_Type = {
     0,                                          /* tp_print */
     0,                                          /* tp_getattr */
     0,                                          /* tp_setattr */
-    0,                                          /* tp_reserved */
+    0,                                          /* tp_as_async */
     (reprfunc)gen_repr,                         /* tp_repr */
     0,                                          /* tp_as_number */
     0,                                          /* tp_as_sequence */
@@ -499,7 +602,7 @@ PyTypeObject PyGen_Type = {
     0,                                          /* tp_clear */
     0,                                          /* tp_richcompare */
     offsetof(PyGenObject, gi_weakreflist),      /* tp_weaklistoffset */
-    PyObject_SelfIter,                          /* tp_iter */
+    (getiterfunc)gen_get_iter,                  /* tp_iter */
     (iternextfunc)gen_iternext,                 /* tp_iternext */
     gen_methods,                                /* tp_methods */
     gen_memberlist,                             /* tp_members */
@@ -526,7 +629,7 @@ PyTypeObject PyGen_Type = {
 };
 
 PyObject *
-PyGen_New(PyFrameObject *f)
+PyGen_NewWithQualName(PyFrameObject *f, PyObject *name, PyObject *qualname)
 {
     PyGenObject *gen = PyObject_GC_New(PyGenObject, &PyGen_Type);
     if (gen == NULL) {
@@ -539,10 +642,26 @@ PyGen_New(PyFrameObject *f)
     gen->gi_code = (PyObject *)(f->f_code);
     gen->gi_running = 0;
     gen->gi_weakreflist = NULL;
+    if (name != NULL)
+        gen->gi_name = name;
+    else
+        gen->gi_name = ((PyCodeObject *)gen->gi_code)->co_name;
+    Py_INCREF(gen->gi_name);
+    if (qualname != NULL)
+        gen->gi_qualname = qualname;
+    else
+        gen->gi_qualname = gen->gi_name;
+    Py_INCREF(gen->gi_qualname);
     _PyObject_GC_TRACK(gen);
     return (PyObject *)gen;
 }
 
+PyObject *
+PyGen_New(PyFrameObject *f)
+{
+    return PyGen_NewWithQualName(f, NULL, NULL);
+}
+
 int
 PyGen_NeedsFinalizing(PyGenObject *gen)
 {
@@ -560,3 +679,57 @@ PyGen_NeedsFinalizing(PyGenObject *gen)
     /* No blocks except loops, it's safe to skip finalization. */
     return 0;
 }
+
+/*
+ *   This helper function returns an awaitable for `o`:
+ *     - `o` if `o` is a coroutine-object;
+ *     - `type(o)->tp_as_async->am_await(o)`
+ *
+ *   Raises a TypeError if it's not possible to return
+ *   an awaitable and returns NULL.
+ */
+PyObject *
+_PyGen_GetAwaitableIter(PyObject *o)
+{
+    getawaitablefunc getter = NULL;
+    PyTypeObject *ot;
+
+    if (PyGen_CheckCoroutineExact(o)) {
+        /* Fast path. It's a central function for 'await'. */
+        Py_INCREF(o);
+        return o;
+    }
+
+    ot = Py_TYPE(o);
+    if (ot->tp_as_async != NULL) {
+        getter = ot->tp_as_async->am_await;
+    }
+    if (getter != NULL) {
+        PyObject *res = (*getter)(o);
+        if (res != NULL) {
+            if (!PyIter_Check(res)) {
+                PyErr_Format(PyExc_TypeError,
+                             "__await__() returned non-iterator "
+                             "of type '%.100s'",
+                             Py_TYPE(res)->tp_name);
+                Py_CLEAR(res);
+            }
+            else {
+                if (PyGen_CheckCoroutineExact(res)) {
+                    /* __await__ must return an *iterator*, not
+                       a coroutine or another awaitable (see PEP 492) */
+                    PyErr_SetString(PyExc_TypeError,
+                                    "__await__() returned a coroutine");
+                    Py_CLEAR(res);
+                }
+            }
+        }
+        return res;
+    }
+
+    PyErr_Format(PyExc_TypeError,
+                 "object %.100s can't be used in 'await' expression",
+                 ot->tp_name);
+
+    return NULL;
+}