New submission from STINNER Victor <vstin...@python.org>:
Building Mercurial with Python 3.9.0rc1 fails with the error: SystemError: <built-in function compile> returned NULL without setting an error The problem comes from the PyAST_Check() function. This function calls get_global_ast_state() which gets the state of the _ast module. If the module is not imported yet, it is imported. The problem is that Mercurial monkey-patches the __import__() builtin function to implement lazy imports. get_global_ast_state() calls PyImport_Import() which returns a Mercurial _LazyModule(__name__='_ast', ...) object. Calling get_ast_state() (PyModule_GetState()) on it is unsafe since it's not the _ast extension module, but another module (which has no state, PyModule_GetState() returns NULL). https://bugzilla.redhat.com/show_bug.cgi?id=1871992#c1 -- The _ast extension module was modified multiple times recently: * September 2019: The extension was converted to PEP 384 (stable ABI): bpo-38113, commit ac46eb4ad6662cf6d771b20d8963658b2186c48c * July 2020: The extension was converted to PEP 489 (multiphase init): bpo-41194, commit b1cc6ba73a51d5cc3aeb113b5e7378fb50a0e20a * (and bugfixes: see bpo-41194 and bpo-41204) I did the PEP 489 change to fix a regression caused by the first change (PEP 384), two bugs in fact: * bpo-41194 Python 3.9.0b3 crash on compile() in PyAST_Check() when the _ast module is loaded more than once * bpo-41261: 3.9-dev SEGV in object_recursive_isinstance in ast.literal_eval ---------- components: Library (Lib) messages: 375881 nosy: vstinner priority: release blocker severity: normal status: open title: _ast module: get_global_ast_state() doesn't work with Mercurial lazy import versions: Python 3.10, Python 3.9 _______________________________________ Python tracker <rep...@bugs.python.org> <https://bugs.python.org/issue41631> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
