Backport for issue1265 (pdb bug with "with" statement).
When an unfinished generator-iterator is garbage collected, PyEval_EvalFrameEx
is called with a GeneratorExit exception set. This leads to funny results
if the sys.settrace function itself makes use of generators.
A visible effect is that the settrace function is reset to None.
Another is that the eventual "finally" block of the generator is not called.
It is necessary to save/restore the exception around the call to the trace
function.
This happens a lot with py3k: isinstance() of an ABCMeta instance runs
def __instancecheck__(cls, instance):
"""Override for isinstance(instance, cls)."""
return any(cls.__subclasscheck__(c)
for c in {instance.__class__, type(instance)})
which lets an opened generator expression each time it returns True.
And the problem can be reproduced in 2.5 with pure python code.
diff --git a/Misc/NEWS b/Misc/NEWS
index be3a362..ab86a14 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -12,6 +12,10 @@
Core and builtins
-----------------
+- Issue #1265: Fix a problem with sys.settrace, if the tracing function uses a
+ generator expression when at the same time the executed code is closing a
+ paused generator.
+
- Issue 1704621: Fix segfaults in list_repeat() and list_inplace_repeat().
- Issue #1147: Generators were not raising a DeprecationWarning when a string