[Python-checkins] r85896 - in python/branches/py3k: Include/pyerrors.h Lib/test/test_exceptions.py Misc/NEWS Objects/exceptions.c Python/errors.c
antoine.pitrou
python-checkins at python.org
Fri Oct 29 00:56:58 CEST 2010
Author: antoine.pitrou
Date: Fri Oct 29 00:56:58 2010
New Revision: 85896
Log:
Issue #5437: A preallocated MemoryError instance should not hold traceback
data (including local variables caught in the stack trace) alive infinitely.
Modified:
python/branches/py3k/Include/pyerrors.h
python/branches/py3k/Lib/test/test_exceptions.py
python/branches/py3k/Misc/NEWS
python/branches/py3k/Objects/exceptions.c
python/branches/py3k/Python/errors.c
Modified: python/branches/py3k/Include/pyerrors.h
==============================================================================
--- python/branches/py3k/Include/pyerrors.h (original)
+++ python/branches/py3k/Include/pyerrors.h Fri Oct 29 00:56:58 2010
@@ -156,7 +156,6 @@
PyAPI_DATA(PyObject *) PyExc_BufferError;
-PyAPI_DATA(PyObject *) PyExc_MemoryErrorInst;
PyAPI_DATA(PyObject *) PyExc_RecursionErrorInst;
/* Predefined warning categories */
Modified: python/branches/py3k/Lib/test/test_exceptions.py
==============================================================================
--- python/branches/py3k/Lib/test/test_exceptions.py (original)
+++ python/branches/py3k/Lib/test/test_exceptions.py Fri Oct 29 00:56:58 2010
@@ -721,6 +721,45 @@
self.assertEqual(error5.a, 1)
self.assertEqual(error5.__doc__, "")
+ def test_memory_error_cleanup(self):
+ # Issue #5437: preallocated MemoryError instances should not keep
+ # traceback objects alive.
+ from _testcapi import raise_memoryerror
+ class C:
+ pass
+ wr = None
+ def inner():
+ nonlocal wr
+ c = C()
+ wr = weakref.ref(c)
+ raise_memoryerror()
+ # We cannot use assertRaises since it manually deletes the traceback
+ try:
+ inner()
+ except MemoryError as e:
+ self.assertNotEqual(wr(), None)
+ else:
+ self.fail("MemoryError not raised")
+ self.assertEqual(wr(), None)
+
+ def test_recursion_error_cleanup(self):
+ # Same test as above, but with "recursion exceeded" errors
+ class C:
+ pass
+ wr = None
+ def inner():
+ nonlocal wr
+ c = C()
+ wr = weakref.ref(c)
+ inner()
+ # We cannot use assertRaises since it manually deletes the traceback
+ try:
+ inner()
+ except RuntimeError as e:
+ self.assertNotEqual(wr(), None)
+ else:
+ self.fail("RuntimeError not raised")
+ self.assertEqual(wr(), None)
def test_main():
run_unittest(ExceptionTests)
Modified: python/branches/py3k/Misc/NEWS
==============================================================================
--- python/branches/py3k/Misc/NEWS (original)
+++ python/branches/py3k/Misc/NEWS Fri Oct 29 00:56:58 2010
@@ -10,6 +10,9 @@
Core and Builtins
-----------------
+- Issue #5437: A preallocated MemoryError instance should not hold traceback
+ data (including local variables caught in the stack trace) alive infinitely.
+
- Issue #10186: Fix the SyntaxError caret when the offset is equal to the length
of the offending line.
Modified: python/branches/py3k/Objects/exceptions.c
==============================================================================
--- python/branches/py3k/Objects/exceptions.c (original)
+++ python/branches/py3k/Objects/exceptions.c Fri Oct 29 00:56:58 2010
@@ -1777,7 +1777,91 @@
/*
* MemoryError extends Exception
*/
-SimpleExtendsException(PyExc_Exception, MemoryError, "Out of memory.");
+
+#define MEMERRORS_SAVE 16
+static PyBaseExceptionObject *memerrors_freelist = NULL;
+static int memerrors_numfree = 0;
+
+static PyObject *
+MemoryError_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
+{
+ PyBaseExceptionObject *self;
+
+ if (type != (PyTypeObject *) PyExc_MemoryError)
+ return BaseException_new(type, args, kwds);
+ if (memerrors_freelist == NULL)
+ return BaseException_new(type, args, kwds);
+ /* Fetch object from freelist and revive it */
+ self = memerrors_freelist;
+ self->args = PyTuple_New(0);
+ /* This shouldn't happen since the empty tuple is persistent */
+ if (self->args == NULL)
+ return NULL;
+ memerrors_freelist = (PyBaseExceptionObject *) self->dict;
+ memerrors_numfree--;
+ self->dict = NULL;
+ _Py_NewReference((PyObject *)self);
+ _PyObject_GC_TRACK(self);
+ return (PyObject *)self;
+}
+
+static void
+MemoryError_dealloc(PyBaseExceptionObject *self)
+{
+ _PyObject_GC_UNTRACK(self);
+ BaseException_clear(self);
+ if (memerrors_numfree >= MEMERRORS_SAVE)
+ Py_TYPE(self)->tp_free((PyObject *)self);
+ else {
+ self->dict = (PyObject *) memerrors_freelist;
+ memerrors_freelist = self;
+ memerrors_numfree++;
+ }
+}
+
+static void
+preallocate_memerrors(void)
+{
+ /* We create enough MemoryErrors and then decref them, which will fill
+ up the freelist. */
+ int i;
+ PyObject *errors[MEMERRORS_SAVE];
+ for (i = 0; i < MEMERRORS_SAVE; i++) {
+ errors[i] = MemoryError_new((PyTypeObject *) PyExc_MemoryError,
+ NULL, NULL);
+ if (!errors[i])
+ Py_FatalError("Could not preallocate MemoryError object");
+ }
+ for (i = 0; i < MEMERRORS_SAVE; i++) {
+ Py_DECREF(errors[i]);
+ }
+}
+
+static void
+free_preallocated_memerrors(void)
+{
+ while (memerrors_freelist != NULL) {
+ PyObject *self = (PyObject *) memerrors_freelist;
+ memerrors_freelist = (PyBaseExceptionObject *) memerrors_freelist->dict;
+ Py_TYPE(self)->tp_free((PyObject *)self);
+ }
+}
+
+
+static PyTypeObject _PyExc_MemoryError = {
+ PyVarObject_HEAD_INIT(NULL, 0)
+ "MemoryError",
+ sizeof(PyBaseExceptionObject),
+ 0, (destructor)MemoryError_dealloc, 0, 0, 0, 0, 0, 0, 0,
+ 0, 0, 0, 0, 0, 0, 0,
+ Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE | Py_TPFLAGS_HAVE_GC,
+ PyDoc_STR("Out of memory."), (traverseproc)BaseException_traverse,
+ (inquiry)BaseException_clear, 0, 0, 0, 0, 0, 0, 0, &_PyExc_Exception,
+ 0, 0, 0, offsetof(PyBaseExceptionObject, dict),
+ (initproc)BaseException_init, 0, MemoryError_new
+};
+PyObject *PyExc_MemoryError = (PyObject *) &_PyExc_MemoryError;
+
/*
* BufferError extends Exception
@@ -1869,11 +1953,6 @@
-/* Pre-computed MemoryError instance. Best to create this as early as
- * possible and not wait until a MemoryError is actually raised!
- */
-PyObject *PyExc_MemoryErrorInst=NULL;
-
/* Pre-computed RuntimeError instance for when recursion depth is reached.
Meant to be used when normalizing the exception for exceeding the recursion
depth will cause its own infinite recursion.
@@ -2012,9 +2091,7 @@
POST_INIT(BytesWarning)
POST_INIT(ResourceWarning)
- PyExc_MemoryErrorInst = BaseException_new(&_PyExc_MemoryError, NULL, NULL);
- if (!PyExc_MemoryErrorInst)
- Py_FatalError("Cannot pre-allocate MemoryError instance");
+ preallocate_memerrors();
PyExc_RecursionErrorInst = BaseException_new(&_PyExc_RuntimeError, NULL, NULL);
if (!PyExc_RecursionErrorInst)
@@ -2045,6 +2122,6 @@
void
_PyExc_Fini(void)
{
- Py_CLEAR(PyExc_MemoryErrorInst);
Py_CLEAR(PyExc_RecursionErrorInst);
+ free_preallocated_memerrors();
}
Modified: python/branches/py3k/Python/errors.c
==============================================================================
--- python/branches/py3k/Python/errors.c (original)
+++ python/branches/py3k/Python/errors.c Fri Oct 29 00:56:58 2010
@@ -333,29 +333,7 @@
PyObject *
PyErr_NoMemory(void)
{
- if (PyErr_ExceptionMatches(PyExc_MemoryError))
- /* already current */
- return NULL;
-
- /* raise the pre-allocated instance if it still exists */
- if (PyExc_MemoryErrorInst)
- {
- /* Clear the previous traceback, otherwise it will be appended
- * to the current one.
- *
- * The following statement is not likely to raise any error;
- * if it does, we simply discard it.
- */
- PyException_SetTraceback(PyExc_MemoryErrorInst, Py_None);
-
- PyErr_SetObject(PyExc_MemoryError, PyExc_MemoryErrorInst);
- }
- else
- /* this will probably fail since there's no memory and hee,
- hee, we have to instantiate this class
- */
- PyErr_SetNone(PyExc_MemoryError);
-
+ PyErr_SetNone(PyExc_MemoryError);
return NULL;
}
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