diff options
| -rw-r--r-- | Doc/glossary.rst | 13 | ||||
| -rw-r--r-- | Doc/library/gc.rst | 6 | ||||
| -rw-r--r-- | Doc/library/sys.rst | 8 | ||||
| -rw-r--r-- | Doc/library/weakref.rst | 6 | ||||
| -rw-r--r-- | Lib/test/test_sys.py | 21 | ||||
| -rw-r--r-- | Misc/NEWS | 3 | ||||
| -rw-r--r-- | Python/sysmodule.c | 11 |
7 files changed, 62 insertions, 6 deletions
diff --git a/Doc/glossary.rst b/Doc/glossary.rst index 92877bd896..87e2d8a672 100644 --- a/Doc/glossary.rst +++ b/Doc/glossary.rst @@ -402,6 +402,19 @@ Glossary than compiled ones, though their programs generally also run more slowly. See also :term:`interactive`. + interpreter shutdown + When asked to shut down, the Python interpreter enters a special phase + where it gradually releases all allocated resources, such as modules + and various critical internal structures. It also makes several calls + to the :term:`garbage collector <garbage collection>`. This can trigger + the execution of code in user-defined destructors or weakref callbacks. + Code executed during the shutdown phase can encounter various + exceptions as the resources it relies on may not function anymore + (common examples are library modules or the warnings machinery). + + The main reason for interpreter shutdown is that the ``__main__`` module + or the script being run has finished executing. + iterable An object capable of returning its members one at a time. Examples of iterables include all sequence types (such as :class:`list`, :class:`str`, diff --git a/Doc/library/gc.rst b/Doc/library/gc.rst index 813554206a..d11c2e1282 100644 --- a/Doc/library/gc.rst +++ b/Doc/library/gc.rst @@ -186,7 +186,7 @@ values but should not rebind them): added to this list rather than freed. .. versionchanged:: 3.2 - If this list is non-empty at interpreter shutdown, a + If this list is non-empty at :term:`interpreter shutdown`, a :exc:`ResourceWarning` is emitted, which is silent by default. If :const:`DEBUG_UNCOLLECTABLE` is set, in addition all uncollectable objects are printed. @@ -252,8 +252,8 @@ The following constants are provided for use with :func:`set_debug`: to the ``garbage`` list. .. versionchanged:: 3.2 - Also print the contents of the :data:`garbage` list at interpreter - shutdown, if it isn't empty. + Also print the contents of the :data:`garbage` list at + :term:`interpreter shutdown`, if it isn't empty. .. data:: DEBUG_SAVEALL diff --git a/Doc/library/sys.rst b/Doc/library/sys.rst index 3024086a22..fa125a0c96 100644 --- a/Doc/library/sys.rst +++ b/Doc/library/sys.rst @@ -718,6 +718,14 @@ always available. value of :func:`intern` around to benefit from it. +.. function:: is_finalizing() + + Return :const:`True` if the Python interpreter is + :term:`shutting down <interpreter shutdown>`, :const:`False` otherwise. + + .. versionadded:: 3.5 + + .. data:: last_type last_value last_traceback diff --git a/Doc/library/weakref.rst b/Doc/library/weakref.rst index cc883b1b51..2e16077b8a 100644 --- a/Doc/library/weakref.rst +++ b/Doc/library/weakref.rst @@ -258,7 +258,7 @@ These method have the same issues as the and :meth:`keyrefs` method of are called in reverse order of creation. A finalizer will never invoke its callback during the later part of - the interpreter shutdown when module globals are liable to have + the :term:`interpreter shutdown` when module globals are liable to have been replaced by :const:`None`. .. method:: __call__() @@ -527,8 +527,8 @@ follows:: Starting with Python 3.4, :meth:`__del__` methods no longer prevent reference cycles from being garbage collected, and module globals are -no longer forced to :const:`None` during interpreter shutdown. So this -code should work without any issues on CPython. +no longer forced to :const:`None` during :term:`interpreter shutdown`. +So this code should work without any issues on CPython. However, handling of :meth:`__del__` methods is notoriously implementation specific, since it depends on internal details of the interpreter's garbage diff --git a/Lib/test/test_sys.py b/Lib/test/test_sys.py index 9ac105fe38..ec2eaf3bab 100644 --- a/Lib/test/test_sys.py +++ b/Lib/test/test_sys.py @@ -744,6 +744,27 @@ class SysModuleTest(unittest.TestCase): c = sys.getallocatedblocks() self.assertIn(c, range(b - 50, b + 50)) + def test_is_finalizing(self): + self.assertIs(sys.is_finalizing(), False) + # Don't use the atexit module because _Py_Finalizing is only set + # after calling atexit callbacks + code = """if 1: + import sys + + class AtExit: + is_finalizing = sys.is_finalizing + print = print + + def __del__(self): + self.print(self.is_finalizing(), flush=True) + + # Keep a reference in the __main__ module namespace, so the + # AtExit destructor will be called at Python exit + ref = AtExit() + """ + rc, stdout, stderr = assert_python_ok('-c', code) + self.assertEqual(stdout.rstrip(), b'True') + @test.support.cpython_only class SizeofTest(unittest.TestCase): @@ -194,6 +194,9 @@ Core and Builtins Library ------- +- Issue #22696: Add function :func:`sys.is_finalizing` to know about + interpreter shutdown. + - Issue #16043: Add a default limit for the amount of data xmlrpclib.gzip_decode will return. This resolves CVE-2013-1753. diff --git a/Python/sysmodule.c b/Python/sysmodule.c index 6fb882f015..aa4046ff93 100644 --- a/Python/sysmodule.c +++ b/Python/sysmodule.c @@ -1121,6 +1121,16 @@ PyDoc_STRVAR(sys_clear_type_cache__doc__, "_clear_type_cache() -> None\n\ Clear the internal type lookup cache."); +static PyObject * +sys_is_finalizing(PyObject* self, PyObject* args) +{ + return PyBool_FromLong(_Py_Finalizing != NULL); +} + +PyDoc_STRVAR(is_finalizing_doc, +"is_finalizing()\n\ +Return True if Python is exiting."); + static PyMethodDef sys_methods[] = { /* Might as well keep this in alphabetic order */ @@ -1167,6 +1177,7 @@ static PyMethodDef sys_methods[] = { getwindowsversion_doc}, #endif /* MS_WINDOWS */ {"intern", sys_intern, METH_VARARGS, intern_doc}, + {"is_finalizing", sys_is_finalizing, METH_NOARGS, is_finalizing_doc}, #ifdef USE_MALLOPT {"mdebug", sys_mdebug, METH_VARARGS}, #endif |