[Python-checkins] cpython: Issue #19255: The builtins module is restored to initial value before
serhiy.storchaka
python-checkins at python.org
Mon Feb 10 17:21:58 CET 2014
http://hg.python.org/cpython/rev/6a1711c96fa6
changeset: 89097:6a1711c96fa6
user: Serhiy Storchaka <storchaka at gmail.com>
date: Mon Feb 10 18:21:34 2014 +0200
summary:
Issue #19255: The builtins module is restored to initial value before
cleaning other modules. The sys and builtins modules are cleaned last.
files:
Include/moduleobject.h | 1 +
Include/pystate.h | 2 +-
Lib/test/test_builtin.py | 29 +++++++++
Misc/NEWS | 3 +
Objects/moduleobject.c | 13 ++-
Python/import.c | 85 +++++++++++++++++----------
Python/pystate.c | 2 +
7 files changed, 96 insertions(+), 39 deletions(-)
diff --git a/Include/moduleobject.h b/Include/moduleobject.h
--- a/Include/moduleobject.h
+++ b/Include/moduleobject.h
@@ -25,6 +25,7 @@
PyAPI_FUNC(PyObject *) PyModule_GetFilenameObject(PyObject *);
#ifndef Py_LIMITED_API
PyAPI_FUNC(void) _PyModule_Clear(PyObject *);
+PyAPI_FUNC(void) _PyModule_ClearDict(PyObject *);
#endif
PyAPI_FUNC(struct PyModuleDef*) PyModule_GetDef(PyObject*);
PyAPI_FUNC(void*) PyModule_GetState(PyObject*);
diff --git a/Include/pystate.h b/Include/pystate.h
--- a/Include/pystate.h
+++ b/Include/pystate.h
@@ -33,7 +33,6 @@
int codecs_initialized;
int fscodec_initialized;
-
#ifdef HAVE_DLOPEN
int dlopenflags;
#endif
@@ -41,6 +40,7 @@
int tscdump;
#endif
+ PyObject *builtins_copy;
} PyInterpreterState;
#endif
diff --git a/Lib/test/test_builtin.py b/Lib/test/test_builtin.py
--- a/Lib/test/test_builtin.py
+++ b/Lib/test/test_builtin.py
@@ -16,6 +16,7 @@
import warnings
from operator import neg
from test.support import TESTFN, unlink, run_unittest, check_warnings
+from test.script_helper import assert_python_ok
try:
import pty, signal
except ImportError:
@@ -1592,6 +1593,34 @@
data = 'The quick Brown fox Jumped over The lazy Dog'.split()
self.assertRaises(TypeError, sorted, data, None, lambda x,y: 0)
+
+class ShutdownTest(unittest.TestCase):
+
+ def test_cleanup(self):
+ # Issue #19255: builtins are still available at shutdown
+ code = """if 1:
+ import builtins
+ import sys
+
+ class C:
+ def __del__(self):
+ print("before")
+ # Check that builtins still exist
+ len(())
+ print("after")
+
+ c = C()
+ # Make this module survive until builtins and sys are cleaned
+ builtins.here = sys.modules[__name__]
+ sys.here = sys.modules[__name__]
+ # Create a reference loop so that this module needs to go
+ # through a GC phase.
+ here = sys.modules[__name__]
+ """
+ rc, out, err = assert_python_ok("-c", code)
+ self.assertEqual(["before", "after"], out.decode().splitlines())
+
+
def load_tests(loader, tests, pattern):
from doctest import DocTestSuite
tests.addTest(DocTestSuite(builtins))
diff --git a/Misc/NEWS b/Misc/NEWS
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -10,6 +10,9 @@
Core and Builtins
-----------------
+- Issue #19255: The builtins module is restored to initial value before
+ cleaning other modules. The sys and builtins modules are cleaned last.
+
- Issue #20437: Fixed 22 potential bugs when deleting objects references.
- Issue #20500: Displaying an exception at interpreter shutdown no longer
diff --git a/Objects/moduleobject.c b/Objects/moduleobject.c
--- a/Objects/moduleobject.c
+++ b/Objects/moduleobject.c
@@ -299,6 +299,14 @@
void
_PyModule_Clear(PyObject *m)
{
+ PyObject *d = ((PyModuleObject *)m)->md_dict;
+ if (d != NULL)
+ _PyModule_ClearDict(d);
+}
+
+void
+_PyModule_ClearDict(PyObject *d)
+{
/* To make the execution order of destructors for global
objects a bit more predictable, we first zap all objects
whose name starts with a single underscore, before we clear
@@ -308,11 +316,6 @@
Py_ssize_t pos;
PyObject *key, *value;
- PyObject *d;
-
- d = ((PyModuleObject *)m)->md_dict;
- if (d == NULL)
- return;
/* First, clear only names starting with a single underscore */
pos = 0;
diff --git a/Python/import.c b/Python/import.c
--- a/Python/import.c
+++ b/Python/import.c
@@ -49,9 +49,13 @@
void
_PyImport_Init(void)
{
+ PyInterpreterState *interp = PyThreadState_Get()->interp;
initstr = PyUnicode_InternFromString("__init__");
if (initstr == NULL)
Py_FatalError("Can't initialize import variables");
+ interp->builtins_copy = PyDict_Copy(interp->builtins);
+ if (interp->builtins_copy == NULL)
+ Py_FatalError("Can't backup builtins dict");
}
void
@@ -397,8 +401,10 @@
PyObject *key, *value, *dict;
PyInterpreterState *interp = PyThreadState_GET()->interp;
PyObject *modules = interp->modules;
- PyObject *builtins = interp->builtins;
+ PyObject *builtins_mod = NULL;
+ PyObject *sys_mod = NULL;
PyObject *weaklist = NULL;
+ char **p;
if (modules == NULL)
return; /* Already done */
@@ -411,31 +417,22 @@
/* XXX Perhaps these precautions are obsolete. Who knows? */
- value = PyDict_GetItemString(modules, "builtins");
- if (value != NULL && PyModule_Check(value)) {
- dict = PyModule_GetDict(value);
+ if (Py_VerboseFlag)
+ PySys_WriteStderr("# clear builtins._\n");
+ PyDict_SetItemString(interp->builtins, "_", Py_None);
+
+ for (p = sys_deletes; *p != NULL; p++) {
if (Py_VerboseFlag)
- PySys_WriteStderr("# clear builtins._\n");
- PyDict_SetItemString(dict, "_", Py_None);
+ PySys_WriteStderr("# clear sys.%s\n", *p);
+ PyDict_SetItemString(interp->sysdict, *p, Py_None);
}
- value = PyDict_GetItemString(modules, "sys");
- if (value != NULL && PyModule_Check(value)) {
- char **p;
- PyObject *v;
- dict = PyModule_GetDict(value);
- for (p = sys_deletes; *p != NULL; p++) {
- if (Py_VerboseFlag)
- PySys_WriteStderr("# clear sys.%s\n", *p);
- PyDict_SetItemString(dict, *p, Py_None);
- }
- for (p = sys_files; *p != NULL; p+=2) {
- if (Py_VerboseFlag)
- PySys_WriteStderr("# restore sys.%s\n", *p);
- v = PyDict_GetItemString(dict, *(p+1));
- if (v == NULL)
- v = Py_None;
- PyDict_SetItemString(dict, *p, v);
- }
+ for (p = sys_files; *p != NULL; p+=2) {
+ if (Py_VerboseFlag)
+ PySys_WriteStderr("# restore sys.%s\n", *p);
+ value = PyDict_GetItemString(interp->sysdict, *(p+1));
+ if (value == NULL)
+ value = Py_None;
+ PyDict_SetItemString(interp->sysdict, *p, value);
}
/* We prepare a list which will receive (name, weakref) tuples of
@@ -473,11 +470,15 @@
/* Clear the modules dict. */
PyDict_Clear(modules);
- /* Replace the interpreter's reference to builtins with an empty dict
- (module globals still have a reference to the original builtins). */
- builtins = interp->builtins;
- interp->builtins = PyDict_New();
- Py_DECREF(builtins);
+ /* Restore the original builtins dict, to ensure that any
+ user data gets cleared. */
+ dict = PyDict_Copy(interp->builtins);
+ if (dict == NULL)
+ PyErr_Clear();
+ PyDict_Clear(interp->builtins);
+ if (PyDict_Update(interp->builtins, interp->builtins_copy))
+ PyErr_Clear();
+ Py_XDECREF(dict);
/* Clear module dict copies stored in the interpreter state */
_PyState_ClearModules();
/* Collect references */
@@ -488,7 +489,15 @@
/* Now, if there are any modules left alive, clear their globals to
minimize potential leaks. All C extension modules actually end
- up here, since they are kept alive in the interpreter state. */
+ up here, since they are kept alive in the interpreter state.
+
+ The special treatment of "builtins" here is because even
+ when it's not referenced as a module, its dictionary is
+ referenced by almost every module's __builtins__. Since
+ deleting a module clears its dictionary (even if there are
+ references left to it), we need to delete the "builtins"
+ module last. Likewise, we don't delete sys until the very
+ end because it is implicitly referenced (e.g. by print). */
if (weaklist != NULL) {
Py_ssize_t i, n;
n = PyList_GET_SIZE(weaklist);
@@ -498,17 +507,27 @@
PyObject *mod = PyWeakref_GET_OBJECT(PyTuple_GET_ITEM(tup, 1));
if (mod == Py_None)
continue;
+ assert(PyModule_Check(mod));
+ dict = PyModule_GetDict(mod);
+ if (dict == interp->builtins || dict == interp->sysdict)
+ continue;
Py_INCREF(mod);
- assert(PyModule_Check(mod));
if (Py_VerboseFlag && PyUnicode_Check(name))
- PySys_FormatStderr("# cleanup[3] wiping %U\n",
- name, mod);
+ PySys_FormatStderr("# cleanup[3] wiping %U\n", name);
_PyModule_Clear(mod);
Py_DECREF(mod);
}
Py_DECREF(weaklist);
}
+ /* Next, delete sys and builtins (in that order) */
+ if (Py_VerboseFlag)
+ PySys_FormatStderr("# cleanup[3] wiping sys\n");
+ _PyModule_ClearDict(interp->sysdict);
+ if (Py_VerboseFlag)
+ PySys_FormatStderr("# cleanup[3] wiping builtins\n");
+ _PyModule_ClearDict(interp->builtins);
+
/* Clear and delete the modules directory. Actual modules will
still be there only if imported during the execution of some
destructor. */
diff --git a/Python/pystate.c b/Python/pystate.c
--- a/Python/pystate.c
+++ b/Python/pystate.c
@@ -72,6 +72,7 @@
interp->modules_by_index = NULL;
interp->sysdict = NULL;
interp->builtins = NULL;
+ interp->builtins_copy = NULL;
interp->tstate_head = NULL;
interp->codec_search_path = NULL;
interp->codec_search_cache = NULL;
@@ -115,6 +116,7 @@
Py_CLEAR(interp->modules_by_index);
Py_CLEAR(interp->sysdict);
Py_CLEAR(interp->builtins);
+ Py_CLEAR(interp->builtins_copy);
Py_CLEAR(interp->importlib);
}
--
Repository URL: http://hg.python.org/cpython
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