[Python-3000-checkins] r66056 - in python/branches/py3k: Lib/test/test_raise.py Misc/NEWS Python/ceval.c Python/errors.c

[amaury.forgeotdarc]

Author: amaury.forgeotdarc
Date: Fri Aug 29 09:13:32 2008
New Revision: 66056

Log:
Issue 3611: in some cases (a __del__ re-raising an exception, when called from inside
an 'except' clause), the exception __context__ would be reset to None.
This crases the interpreter if this precisely happens inside PyErr_SetObject.

- now the __context__ is properly preserved
- in any case, PyErr_SetObject now saves the current exc_value in a local variable, to
avoid such crashes in the future.

Reviewer: Antoine Pitrou.


Modified:
python/branches/py3k/Lib/test/test_raise.py
python/branches/py3k/Misc/NEWS
python/branches/py3k/Python/ceval.c
python/branches/py3k/Python/errors.c

Modified: python/branches/py3k/Lib/test/test_raise.py
==============================================================================
--- python/branches/py3k/Lib/test/test_raise.py (original)
+++ python/branches/py3k/Lib/test/test_raise.py Fri Aug 29 09:13:32 2008
@@ -324,6 +324,30 @@

f()

+ def test_3611(self):
+ # A re-raised exception in a __del__ caused the __context__
+ # to be cleared
+ class C:
+ def __del__(self):
+ try:
+ 1/0
+ except:
+ raise
+
+ def f():
+ x = C()
+ try:
+ try:
+ x.x
+ except AttributeError:
+ del x
+ raise TypeError
+ except Exception as e:
+ self.assertNotEqual(e.__context__, None)
+ self.assert_(isinstance(e.__context__, AttributeError))
+
+ with support.captured_output("stderr"):
+ f()

class TestRemovedFunctionality(unittest.TestCase):
def test_tuples(self):

Modified: python/branches/py3k/Misc/NEWS
==============================================================================
--- python/branches/py3k/Misc/NEWS (original)
+++ python/branches/py3k/Misc/NEWS Fri Aug 29 09:13:32 2008
@@ -12,6 +12,9 @@
Core and Builtins
-----------------

+- Issue #3611: An exception __context__ could be cleared in a complex pattern
+ involving a __del__ method re-raising an exception.
+
- Issue #2534: speed up isinstance() and issubclass() by 50-70%, so as to
match Python 2.5 speed despite the __instancecheck__ / __subclasscheck__
mechanism. In the process, fix a bug where isinstance() and issubclass(),

Modified: python/branches/py3k/Python/ceval.c
==============================================================================
--- python/branches/py3k/Python/ceval.c (original)
+++ python/branches/py3k/Python/ceval.c Fri Aug 29 09:13:32 2008
@@ -2453,11 +2453,6 @@

if (b->b_type == EXCEPT_HANDLER) {
UNWIND_EXCEPT_HANDLER(b);
- if (why == WHY_EXCEPTION && !throwflag) {
- Py_CLEAR(tstate->exc_type);
- Py_CLEAR(tstate->exc_value);
- Py_CLEAR(tstate->exc_traceback);
- }
continue;
}
UNWIND_BLOCK(b);

Modified: python/branches/py3k/Python/errors.c
==============================================================================
--- python/branches/py3k/Python/errors.c (original)
+++ python/branches/py3k/Python/errors.c Fri Aug 29 09:13:32 2008
@@ -53,6 +53,7 @@
PyErr_SetObject(PyObject *exception, PyObject *value)
{
PyThreadState *tstate = PyThreadState_GET();
+ PyObject *exc_value;
PyObject *tb = NULL;

if (exception != NULL &&
@@ -63,8 +64,10 @@
return;
}
Py_XINCREF(value);
- if (tstate->exc_value != NULL && tstate->exc_value != Py_None) {
+ exc_value = tstate->exc_value;
+ if (exc_value != NULL && exc_value != Py_None) {
/* Implicit exception chaining */
+ Py_INCREF(exc_value);
if (value == NULL || !PyExceptionInstance_Check(value)) {
/* We must normalize the value right now */
PyObject *args, *fixed_value;
@@ -88,8 +91,8 @@
This is O(chain length) but context chains are
usually very short. Sensitive readers may try
to inline the call to PyException_GetContext. */
- if (tstate->exc_value != value) {
- PyObject *o = tstate->exc_value, *context;
+ if (exc_value != value) {
+ PyObject *o = exc_value, *context;
while ((context = PyException_GetContext(o))) {
Py_DECREF(context);
if (context == value) {
@@ -98,8 +101,9 @@
}
o = context;
}
- Py_INCREF(tstate->exc_value);
- PyException_SetContext(value, tstate->exc_value);
+ PyException_SetContext(value, exc_value);
+ } else {
+ Py_DECREF(exc_value);
}
}
if (value != NULL && PyExceptionInstance_Check(value))