Hi, I am trying to understand why I am unable to unload my faulthandler module (implemented in C). Antoine pointed me _PyImport_FixupExtensionObject() comment which gave me a first clue:
Modules which do support multiple initialization set their m_size field to a non-negative number (indicating the size of the module-specific state). They are still recorded in the extensions dictionary, to avoid loading shared libraries twice. Ok, so I changed the size from -1 to 0, and so the m_free callback was called at exit. Nice. This is thanks to PyImport_Cleanup() which clears my module attributes. -- But if I do import faulthandler del sys.modules['faulthandler'] del faulthandler the module is never unloaded. There is another secret reference in the interpreter state: state->modules_by_index. This list is cleared at exit (by PyInterpreterState_Clear), but not my module attributes, and some of them are functions pointing to the module. My module attribute are not cleared at exit because PyImport_Cleanup() clears only modules from sys.modules, and my module is no more referenced in sys.modules. The workaround to unload the module is to explicitly clear its attributes: import faulthandler del sys.modules['faulthandler'] faulthandler.__dict__.clear() del faulthandler -- Is there a bug somewhere, or do I misunderstood something important? Note: I implemented m_traversal, but it is not revelant here (you can consider that my module only contains functions). Victor _______________________________________________ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
