New submission from Thomas Wouters: In a submodule of a package, replacing the parent package in sys.modules during import of the package (meaning the only reference to it is in sys.modules) and then importing itself (or something from itself) crashes the interpreter:
centurion:~/python/crasher > cat sa/__init__.py import v1 centurion:~/python/crasher > cat sa/v1/__init__.py import sys sys.modules['sa'] = sys.modules[__name__] import sa centurion:~/python/crasher > python -c 'import sa' Segmentation fault (core dumped) It seems the crash is not entirely deterministic, as we've had the original code this was reduced from run in Python 2.4 and 2.6 for years, and only discovered the crash when switching to 2.7. However, running the reduced testcase crashes for me in all of Python 2.7, 2.6, 2.4 and 2.2, in debug builds and opt builds. Given the nature of the bug I expect debug builds to crash reliably. I haven't found the actual source of the problem, but what seems to happen is that the import mechanism has a borrowed reference to the 'sa' module around, assuming it'll stay alive while the submodules are imported because it's also stored in sys.modules. This assumption is incorrect. However, changing the import in sa/__init__.py into an absolute or explicit relative import seems to fix the problem, which means this probably won't affect Python 3. ---------- components: Interpreter Core messages: 167640 nosy: twouters priority: normal severity: normal status: open title: Crash when modifying sys.modules during import type: crash versions: Python 2.6, Python 2.7 _______________________________________ Python tracker <rep...@bugs.python.org> <http://bugs.python.org/issue15578> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
