_lsprof.c:ptrace_enter_call assumes PyErr_* is clean

[peaker]

BPO	1733973
Nosy	@arigo
Files	cProfile.patch: A patch to the most recent svn cProfile.patch: Removed redundant PyErr_Clear (already done by PyErr_Fetch)

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = None
closed_at = <Date 2007-09-06.08:36:01.201>
created_at = <Date 2007-06-09.08:04:30.000>
labels = ['extension-modules']
title = '_lsprof.c:ptrace_enter_call assumes PyErr_* is clean'
updated_at = <Date 2007-09-06.08:36:01.171>
user = 'https://bugs.python.org/peaker'

bugs.python.org fields:

activity = <Date 2007-09-06.08:36:01.171>
actor = 'arigo'
assignee = 'none'
closed = True
closed_date = <Date 2007-09-06.08:36:01.201>
closer = 'arigo'
components = ['Extension Modules']
creation = <Date 2007-06-09.08:04:30.000>
creator = 'peaker'
dependencies = []
files = ['8039', '8040']
hgrepos = []
issue_num = 1733973
keywords = ['patch']
message_count = 4.0
messages = ['52738', '52739', '52740', '55681']
nosy_count = 2.0
nosy_names = ['arigo', 'peaker']
pr_nums = []
priority = 'normal'
resolution = 'accepted'
stage = None
status = 'closed'
superseder = None
type = None
url = 'https://bugs.python.org/issue1733973'
versions = ['Python 2.6']

[peaker]

_lsprof.c:ptrace_enter_call assumes PyErr_* has no errors.
It assumes this by feeling free to call functions that PyErr_Clear and overwrite PyErr.

This assumption is broken when throwing into a generator. In that case gen_send_ex(.., 1) calls the ptrace_enter_call with an exception already set.

This assumption causes two bugs:
A. The exception thrown into the generator is overwritten and lost. Later it was also cleared.
B. gen_send_ex(..) still returns error-indication, but since the exception was cleared, you get a SystemError (error indication returned but no exception was set).

To fix this, ptrace_enter_call now saves/restores the current PyErr.

The attached patch was applied on the newest trunk svn. I guess it should be applicable without problems on the 2.5 bugfix branch as well.

[peaker]

It seems that bug bpo-1733757 encountered the same bug. See comments on that bug.

[peaker]

File Added: cProfile.patch

[arigo]

Thanks for the patch. Checked in:

• r58004 (trunk)
• r58005 (release25-maint)