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Add a new warning gategory, ResourceWarning, as discussed on python-dev. It is silent by default, 

except when configured --with-pydebug.

Emit this warning from the GC shutdown procedure, rather than just printing to stderr.
This commit is contained in:
Georg Brandl 2010-10-24 15:11:22 +00:00
parent 872a702bbd
commit 08be72d0aa
12 changed files with 80 additions and 30 deletions
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10
Doc/library/exceptions.rst
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@ -410,10 +410,20 @@ module for more information.
Base class for warnings related to Unicode.
.. exception:: BytesWarning
Base class for warnings related to :class:`bytes` and :class:`buffer`.
.. exception:: ResourceWarning
Base class for warnings related to resource usage.
.. versionadded:: 3.2
Exception hierarchy
-------------------

20
Doc/library/gc.rst
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@ -174,17 +174,15 @@ value but should not rebind it):
with :meth:`__del__` methods, and *garbage* can be examined in that case to
verify that no such cycles are being created.
If :const:`DEBUG_SAVEALL` is set, then all unreachable objects will be added to
this list rather than freed.
If :const:`DEBUG_SAVEALL` is set, then all unreachable objects will be added
to this list rather than freed.
.. versionchanged:: 3.2
If this list is non-empty at interpreter shutdown, a warning message
gets printed.
If this list is non-empty at 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.
::
gc: 2 uncollectable objects at shutdown:
Use gc.set_debug(gc.DEBUG_UNCOLLECTABLE) to list them.
The following constants are provided for use with :func:`set_debug`:
@ -203,12 +201,12 @@ The following constants are provided for use with :func:`set_debug`:
.. data:: DEBUG_UNCOLLECTABLE
Print information of uncollectable objects found (objects which are not
reachable but cannot be freed by the collector). These objects will be added to
the ``garbage`` list.
reachable but cannot be freed by the collector). These objects will be added
to the ``garbage`` list.
.. versionchanged:: 3.2
Also print the contents of the :data:`garbage` list at interpreter
shutdown (rather than just its length), if it isn't empty.
shutdown, if it isn't empty.
.. data:: DEBUG_SAVEALL

3
Doc/library/warnings.rst
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@ -82,6 +82,9 @@ following warnings category classes are currently defined:
| :exc:`BytesWarning` | Base category for warnings related to |
| | :class:`bytes` and :class:`buffer`. |
+----------------------------------+-----------------------------------------------+
| :exc:`ResourceWarning` | Base category for warnings related to |
| | resource usage. |
+----------------------------------+-----------------------------------------------+
While these are technically built-in exceptions, they are documented here,

1
Include/pyerrors.h
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@ -170,6 +170,7 @@ PyAPI_DATA(PyObject *) PyExc_FutureWarning;
PyAPI_DATA(PyObject *) PyExc_ImportWarning;
PyAPI_DATA(PyObject *) PyExc_UnicodeWarning;
PyAPI_DATA(PyObject *) PyExc_BytesWarning;
PyAPI_DATA(PyObject *) PyExc_ResourceWarning;
/* Convenience functions */

1
Lib/test/exception_hierarchy.txt
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@ -47,3 +47,4 @@ BaseException
+-- ImportWarning
+-- UnicodeWarning
+-- BytesWarning
+-- ResourceWarning

8
Lib/test/test_gc.py
View File

@ -485,7 +485,7 @@ class GCTests(unittest.TestCase):
gc.set_debug(%s)
"""
def run_command(code):
p = subprocess.Popen([sys.executable, "-c", code],
p = subprocess.Popen([sys.executable, "-Wd", "-c", code],
stdout=subprocess.PIPE,
stderr=subprocess.PIPE)
stdout, stderr = p.communicate()
@ -494,11 +494,13 @@ class GCTests(unittest.TestCase):
return strip_python_stderr(stderr)
stderr = run_command(code % "0")
self.assertIn(b"gc: 2 uncollectable objects at shutdown", stderr)
self.assertIn(b"ResourceWarning: gc: 2 uncollectable objects at "
b"shutdown; use", stderr)
self.assertNotIn(b"<X 'first'>", stderr)
# With DEBUG_UNCOLLECTABLE, the garbage list gets printed
stderr = run_command(code % "gc.DEBUG_UNCOLLECTABLE")
self.assertIn(b"gc: 2 uncollectable objects at shutdown", stderr)
self.assertIn(b"ResourceWarning: gc: 2 uncollectable objects at "
b"shutdown", stderr)
self.assertTrue(
(b"[<X 'first'>, <X 'second'>]" in stderr) or
(b"[<X 'second'>, <X 'first'>]" in stderr), stderr)

7
Lib/warnings.py
View File

@ -383,4 +383,11 @@ if not _warnings_defaults:
else:
bytes_action = "ignore"
simplefilter(bytes_action, category=BytesWarning, append=1)
# resource usage warnings are enabled by default in pydebug mode
if hasattr(sys, 'gettotalrefcount'):
resource_action = "always"
else:
resource_action = "ignore"
simplefilter(resource_action, category=ResourceWarning, append=1)
del _warnings_defaults

2
Misc/NEWS
View File

@ -691,7 +691,7 @@ Extensions
- Issue #8524: Add a detach() method to socket objects, so as to put the socket
into the closed state without closing the underlying file descriptor.
- Issue #477863: Print a warning at shutdown if gc.garbage is not empty.
- Issue #477863: Emit a ResourceWarning at shutdown if gc.garbage is not empty.
- Issue #6869: Fix a refcount problem in the _ctypes extension.

20
Modules/gcmodule.c
View File

@ -1368,11 +1368,16 @@ _PyGC_Fini(void)
{
if (!(debug & DEBUG_SAVEALL)
&& garbage != NULL && PyList_GET_SIZE(garbage) > 0) {
PySys_WriteStderr(
"gc: "
"%" PY_FORMAT_SIZE_T "d uncollectable objects at shutdown:\n",
PyList_GET_SIZE(garbage)
);
char *message;
if (debug & DEBUG_UNCOLLECTABLE)
message = "gc: %" PY_FORMAT_SIZE_T "d uncollectable objects at " \
"shutdown";
else
message = "gc: %" PY_FORMAT_SIZE_T "d uncollectable objects at " \
"shutdown; use gc.set_debug(gc.DEBUG_UNCOLLECTABLE) to list them";
if (PyErr_WarnFormat(PyExc_ResourceWarning, 0, message,
PyList_GET_SIZE(garbage)) < 0)
PyErr_WriteUnraisable(NULL);
if (debug & DEBUG_UNCOLLECTABLE) {
PyObject *repr = NULL, *bytes = NULL;
repr = PyObject_Repr(garbage);
@ -1387,11 +1392,6 @@ _PyGC_Fini(void)
Py_XDECREF(repr);
Py_XDECREF(bytes);
}
else {
PySys_WriteStderr(
" Use gc.set_debug(gc.DEBUG_UNCOLLECTABLE) to list them.\n"
);
}
}
}

10
Objects/exceptions.c
View File

@ -1852,6 +1852,7 @@ SimpleExtendsException(PyExc_Warning, UnicodeWarning,
"Base class for warnings about Unicode related problems, mostly\n"
"related to conversion problems.");
/*
* BytesWarning extends Warning
*/
@ -1860,6 +1861,13 @@ SimpleExtendsException(PyExc_Warning, BytesWarning,
"related to conversion from str or comparing to str.");
/*
* ResourceWarning extends Warning
*/
SimpleExtendsException(PyExc_Warning, ResourceWarning,
"Base class for warnings about resource usage.");
/* Pre-computed MemoryError instance. Best to create this as early as
* possible and not wait until a MemoryError is actually raised!
@ -1939,6 +1947,7 @@ _PyExc_Init(void)
PRE_INIT(ImportWarning)
PRE_INIT(UnicodeWarning)
PRE_INIT(BytesWarning)
PRE_INIT(ResourceWarning)
bltinmod = PyImport_ImportModule("builtins");
if (bltinmod == NULL)
@ -2001,6 +2010,7 @@ _PyExc_Init(void)
POST_INIT(ImportWarning)
POST_INIT(UnicodeWarning)
POST_INIT(BytesWarning)
POST_INIT(ResourceWarning)
PyExc_MemoryErrorInst = BaseException_new(&_PyExc_MemoryError, NULL, NULL);
if (!PyExc_MemoryErrorInst)

22
Python/_warnings.c
View File

@ -835,6 +835,7 @@ create_filter(PyObject *category, const char *action)
static PyObject *ignore_str = NULL;
static PyObject *error_str = NULL;
static PyObject *default_str = NULL;
static PyObject *always_str = NULL;
PyObject *action_obj = NULL;
PyObject *lineno, *result;
@ -862,6 +863,14 @@ create_filter(PyObject *category, const char *action)
}
action_obj = default_str;
}
else if (!strcmp(action, "always")) {
if (always_str == NULL) {
always_str = PyUnicode_InternFromString("always");
if (always_str == NULL)
return NULL;
}
action_obj = always_str;
}
else {
Py_FatalError("unknown action");
}
@ -879,10 +888,10 @@ static PyObject *
init_filters(void)
{
/* Don't silence DeprecationWarning if -3 was used. */
PyObject *filters = PyList_New(4);
PyObject *filters = PyList_New(5);
unsigned int pos = 0; /* Post-incremented in each use. */
unsigned int x;
const char *bytes_action;
const char *bytes_action, *resource_action;
if (filters == NULL)
return NULL;
@ -901,7 +910,14 @@ init_filters(void)
bytes_action = "ignore";
PyList_SET_ITEM(filters, pos++, create_filter(PyExc_BytesWarning,
bytes_action));
/* resource usage warnings are enabled by default in pydebug mode */
#ifdef Py_DEBUG
resource_action = "always";
#else
resource_action = "ignore";
#endif
PyList_SET_ITEM(filters, pos++, create_filter(PyExc_ResourceWarning,
resource_action));
for (x = 0; x < pos; x += 1) {
if (PyList_GET_ITEM(filters, x) == NULL) {
Py_DECREF(filters);

6
Python/errors.c
View File

@ -767,8 +767,10 @@ PyErr_WriteUnraisable(PyObject *obj)
}
Py_XDECREF(moduleName);
}
PyFile_WriteString(" in ", f);
PyFile_WriteObject(obj, f, 0);
if (obj) {
PyFile_WriteString(" in ", f);
PyFile_WriteObject(obj, f, 0);
}
PyFile_WriteString(" ignored\n", f);
PyErr_Clear(); /* Just in case */
}