[Python-checkins] bpo-46417: Py_Finalize() clears static types (GH-30743)
vstinner
webhook-mailer at python.org
Fri Jan 21 07:06:39 EST 2022
https://github.com/python/cpython/commit/595225e86dcc6ea520a584839925a878dce7a9b2
commit: 595225e86dcc6ea520a584839925a878dce7a9b2
branch: main
author: Victor Stinner <vstinner at python.org>
committer: vstinner <vstinner at python.org>
date: 2022-01-21T13:06:34+01:00
summary:
bpo-46417: Py_Finalize() clears static types (GH-30743)
Add _PyTypes_FiniTypes() best-effort function to clear static types:
don't deallocate a type if it still has subclasses.
remove_subclass() now sets tp_subclasses to NULL when removing the
last subclass.
files:
M Include/internal/pycore_typeobject.h
M Objects/object.c
M Objects/typeobject.c
M Python/pylifecycle.c
diff --git a/Include/internal/pycore_typeobject.h b/Include/internal/pycore_typeobject.h
index ba95bbc1c4820..c480a3a57b436 100644
--- a/Include/internal/pycore_typeobject.h
+++ b/Include/internal/pycore_typeobject.h
@@ -13,6 +13,7 @@ extern "C" {
extern PyStatus _PyTypes_InitState(PyInterpreterState *);
extern PyStatus _PyTypes_InitTypes(PyInterpreterState *);
+extern void _PyTypes_FiniTypes(PyInterpreterState *);
extern void _PyTypes_Fini(PyInterpreterState *);
diff --git a/Objects/object.c b/Objects/object.c
index 124485d64ab77..dc2cba2ebccec 100644
--- a/Objects/object.c
+++ b/Objects/object.c
@@ -1837,6 +1837,94 @@ _PyTypes_InitState(PyInterpreterState *interp)
return _PyStatus_OK();
}
+
+static PyTypeObject* static_types[] = {
+ // base types
+ &PyAsyncGen_Type,
+ &PyBool_Type,
+ &PyByteArrayIter_Type,
+ &PyByteArray_Type,
+ &PyCFunction_Type,
+ &PyCallIter_Type,
+ &PyCapsule_Type,
+ &PyCell_Type,
+ &PyClassMethodDescr_Type,
+ &PyClassMethod_Type,
+ &PyCode_Type,
+ &PyComplex_Type,
+ &PyCoro_Type,
+ &PyDictItems_Type,
+ &PyDictIterItem_Type,
+ &PyDictIterKey_Type,
+ &PyDictIterValue_Type,
+ &PyDictKeys_Type,
+ &PyDictProxy_Type,
+ &PyDictRevIterItem_Type,
+ &PyDictRevIterKey_Type,
+ &PyDictRevIterValue_Type,
+ &PyDictValues_Type,
+ &PyDict_Type,
+ &PyEllipsis_Type,
+ &PyEnum_Type,
+ &PyFrame_Type,
+ &PyFrozenSet_Type,
+ &PyFunction_Type,
+ &PyGen_Type,
+ &PyGetSetDescr_Type,
+ &PyInstanceMethod_Type,
+ &PyListIter_Type,
+ &PyListRevIter_Type,
+ &PyList_Type,
+ &PyLongRangeIter_Type,
+ &PyMemberDescr_Type,
+ &PyMemoryView_Type,
+ &PyMethodDescr_Type,
+ &PyMethod_Type,
+ &PyModuleDef_Type,
+ &PyModule_Type,
+ &PyODictIter_Type,
+ &PyPickleBuffer_Type,
+ &PyProperty_Type,
+ &PyRangeIter_Type,
+ &PyRange_Type,
+ &PyReversed_Type,
+ &PySTEntry_Type,
+ &PySeqIter_Type,
+ &PySetIter_Type,
+ &PySet_Type,
+ &PySlice_Type,
+ &PyStaticMethod_Type,
+ &PyStdPrinter_Type,
+ &PySuper_Type,
+ &PyTraceBack_Type,
+ &PyWrapperDescr_Type,
+ &Py_GenericAliasType,
+ &_PyAnextAwaitable_Type,
+ &_PyAsyncGenASend_Type,
+ &_PyAsyncGenAThrow_Type,
+ &_PyAsyncGenWrappedValue_Type,
+ &_PyCoroWrapper_Type,
+ &_PyInterpreterID_Type,
+ &_PyManagedBuffer_Type,
+ &_PyMethodWrapper_Type,
+ &_PyNamespace_Type,
+ &_PyNone_Type,
+ &_PyNotImplemented_Type,
+ &_PyUnion_Type,
+ &_PyWeakref_CallableProxyType,
+ &_PyWeakref_ProxyType,
+ &_PyWeakref_RefType,
+
+ // subclasses: _PyTypes_FiniTypes() deallocates them before their base
+ // class
+ &PyCMethod_Type, // base=&PyCFunction_Type
+ &PyODictItems_Type, // base=&PyDictItems_Type
+ &PyODictKeys_Type, // base=&PyDictKeys_Type
+ &PyODictValues_Type, // base=&PyDictValues_Type
+ &PyODict_Type, // base=&PyDict_Type
+};
+
+
PyStatus
_PyTypes_InitTypes(PyInterpreterState *interp)
{
@@ -1858,91 +1946,44 @@ _PyTypes_InitTypes(PyInterpreterState *interp)
assert(PyType_Type.tp_base == &PyBaseObject_Type);
// All other static types (unless initialized elsewhere)
- INIT_TYPE(PyAsyncGen_Type);
- INIT_TYPE(PyBool_Type);
- INIT_TYPE(PyByteArrayIter_Type);
- INIT_TYPE(PyByteArray_Type);
- INIT_TYPE(PyCFunction_Type);
- INIT_TYPE(PyCMethod_Type);
- INIT_TYPE(PyCallIter_Type);
- INIT_TYPE(PyCapsule_Type);
- INIT_TYPE(PyCell_Type);
- INIT_TYPE(PyClassMethodDescr_Type);
- INIT_TYPE(PyClassMethod_Type);
- INIT_TYPE(PyCode_Type);
- INIT_TYPE(PyComplex_Type);
- INIT_TYPE(PyCoro_Type);
- INIT_TYPE(PyDictItems_Type);
- INIT_TYPE(PyDictIterItem_Type);
- INIT_TYPE(PyDictIterKey_Type);
- INIT_TYPE(PyDictIterValue_Type);
- INIT_TYPE(PyDictKeys_Type);
- INIT_TYPE(PyDictProxy_Type);
- INIT_TYPE(PyDictRevIterItem_Type);
- INIT_TYPE(PyDictRevIterKey_Type);
- INIT_TYPE(PyDictRevIterValue_Type);
- INIT_TYPE(PyDictValues_Type);
- INIT_TYPE(PyDict_Type);
- INIT_TYPE(PyEllipsis_Type);
- INIT_TYPE(PyEnum_Type);
- INIT_TYPE(PyFrame_Type);
- INIT_TYPE(PyFrozenSet_Type);
- INIT_TYPE(PyFunction_Type);
- INIT_TYPE(PyGen_Type);
- INIT_TYPE(PyGetSetDescr_Type);
- INIT_TYPE(PyInstanceMethod_Type);
- INIT_TYPE(PyListIter_Type);
- INIT_TYPE(PyListRevIter_Type);
- INIT_TYPE(PyList_Type);
- INIT_TYPE(PyLongRangeIter_Type);
- INIT_TYPE(PyMemberDescr_Type);
- INIT_TYPE(PyMemoryView_Type);
- INIT_TYPE(PyMethodDescr_Type);
- INIT_TYPE(PyMethod_Type);
- INIT_TYPE(PyModuleDef_Type);
- INIT_TYPE(PyModule_Type);
- INIT_TYPE(PyODictItems_Type);
- INIT_TYPE(PyODictIter_Type);
- INIT_TYPE(PyODictKeys_Type);
- INIT_TYPE(PyODictValues_Type);
- INIT_TYPE(PyODict_Type);
- INIT_TYPE(PyPickleBuffer_Type);
- INIT_TYPE(PyProperty_Type);
- INIT_TYPE(PyRangeIter_Type);
- INIT_TYPE(PyRange_Type);
- INIT_TYPE(PyReversed_Type);
- INIT_TYPE(PySTEntry_Type);
- INIT_TYPE(PySeqIter_Type);
- INIT_TYPE(PySetIter_Type);
- INIT_TYPE(PySet_Type);
- INIT_TYPE(PySlice_Type);
- INIT_TYPE(PyStaticMethod_Type);
- INIT_TYPE(PyStdPrinter_Type);
- INIT_TYPE(PySuper_Type);
- INIT_TYPE(PyTraceBack_Type);
- INIT_TYPE(PyWrapperDescr_Type);
- INIT_TYPE(Py_GenericAliasType);
- INIT_TYPE(_PyAnextAwaitable_Type);
- INIT_TYPE(_PyAsyncGenASend_Type);
- INIT_TYPE(_PyAsyncGenAThrow_Type);
- INIT_TYPE(_PyAsyncGenWrappedValue_Type);
- INIT_TYPE(_PyCoroWrapper_Type);
- INIT_TYPE(_PyInterpreterID_Type);
- INIT_TYPE(_PyManagedBuffer_Type);
- INIT_TYPE(_PyMethodWrapper_Type);
- INIT_TYPE(_PyNamespace_Type);
- INIT_TYPE(_PyNone_Type);
- INIT_TYPE(_PyNotImplemented_Type);
- INIT_TYPE(_PyWeakref_CallableProxyType);
- INIT_TYPE(_PyWeakref_ProxyType);
- INIT_TYPE(_PyWeakref_RefType);
- INIT_TYPE(_PyUnion_Type);
+ for (size_t i=0; i < Py_ARRAY_LENGTH(static_types); i++) {
+ PyTypeObject *type = static_types[i];
+ if (PyType_Ready(type) < 0) {
+ return _PyStatus_ERR("Can't initialize types");
+ }
+ }
return _PyStatus_OK();
#undef INIT_TYPE
}
+// Best-effort function clearing static types.
+//
+// Don't deallocate a type if it still has subclasses. If a Py_Finalize()
+// sub-function is interrupted by CTRL+C or fails with MemoryError, some
+// subclasses are not cleared properly. Leave the static type unchanged in this
+// case.
+void
+_PyTypes_FiniTypes(PyInterpreterState *interp)
+{
+ if (!_Py_IsMainInterpreter(interp)) {
+ return;
+ }
+
+ // Deallocate types in the reverse order to deallocate subclasses before
+ // their base classes.
+ for (Py_ssize_t i=Py_ARRAY_LENGTH(static_types)-1; i>=0; i--) {
+ PyTypeObject *type = static_types[i];
+ // Cannot delete a type if it still has subclasses
+ if (type->tp_subclasses != NULL) {
+ continue;
+ }
+ _PyStaticType_Dealloc(type);
+ }
+}
+
+
void
_Py_NewReference(PyObject *op)
{
diff --git a/Objects/typeobject.c b/Objects/typeobject.c
index 66a10a5bc57dd..97a9a65c36b0e 100644
--- a/Objects/typeobject.c
+++ b/Objects/typeobject.c
@@ -4071,6 +4071,18 @@ extern void
_PyDictKeys_DecRef(PyDictKeysObject *keys);
+static void
+type_dealloc_common(PyTypeObject *type)
+{
+ PyObject *tp, *val, *tb;
+ PyErr_Fetch(&tp, &val, &tb);
+ remove_all_subclasses(type, type->tp_bases);
+ PyErr_Restore(tp, val, tb);
+
+ PyObject_ClearWeakRefs((PyObject *)type);
+}
+
+
void
_PyStaticType_Dealloc(PyTypeObject *type)
{
@@ -4079,11 +4091,14 @@ _PyStaticType_Dealloc(PyTypeObject *type)
// and a type must no longer be used once it's deallocated.
assert(type->tp_subclasses == NULL);
+ type_dealloc_common(type);
+
Py_CLEAR(type->tp_dict);
Py_CLEAR(type->tp_bases);
Py_CLEAR(type->tp_mro);
Py_CLEAR(type->tp_cache);
Py_CLEAR(type->tp_subclasses);
+
type->tp_flags &= ~Py_TPFLAGS_READY;
}
@@ -4091,22 +4106,19 @@ _PyStaticType_Dealloc(PyTypeObject *type)
static void
type_dealloc(PyTypeObject *type)
{
- PyObject *tp, *val, *tb;
-
/* Assert this is a heap-allocated type object */
_PyObject_ASSERT((PyObject *)type, type->tp_flags & Py_TPFLAGS_HEAPTYPE);
_PyObject_GC_UNTRACK(type);
- PyErr_Fetch(&tp, &val, &tb);
- remove_all_subclasses(type, type->tp_bases);
- PyErr_Restore(tp, val, tb);
- PyObject_ClearWeakRefs((PyObject *)type);
+ type_dealloc_common(type);
+
Py_XDECREF(type->tp_base);
Py_XDECREF(type->tp_dict);
Py_XDECREF(type->tp_bases);
Py_XDECREF(type->tp_mro);
Py_XDECREF(type->tp_cache);
Py_XDECREF(type->tp_subclasses);
+
/* A type's tp_doc is heap allocated, unlike the tp_doc slots
* of most other objects. It's okay to cast it to char *.
*/
@@ -6541,6 +6553,10 @@ remove_subclass(PyTypeObject *base, PyTypeObject *type)
PyErr_Clear();
}
Py_XDECREF(key);
+
+ if (PyDict_Size(dict) == 0) {
+ Py_CLEAR(base->tp_subclasses);
+ }
}
static void
diff --git a/Python/pylifecycle.c b/Python/pylifecycle.c
index 5572f61c7288a..662e578818349 100644
--- a/Python/pylifecycle.c
+++ b/Python/pylifecycle.c
@@ -1676,6 +1676,7 @@ finalize_interp_types(PyInterpreterState *interp)
_PyThread_FiniType(interp);
_PyErr_FiniTypes(interp);
_PyTypes_Fini(interp);
+ _PyTypes_FiniTypes(interp);
// Call _PyUnicode_ClearInterned() before _PyDict_Fini() since it uses
// a dict internally.
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