New submission from STINNER Victor <vstin...@python.org>:
Writing an unit test on the Python codecs machinery is facing a practical problem: there is no C nor Python API to unregister a codec search function. It's even documented in a note of the codecs.register() function: "Note: Search function registration is not currently reversible, which may cause problems in some cases, such as unit testing or module reloading." https://docs.python.org/dev/library/codecs.html#codecs.register test_codecs contains a long comment about that: # There's no way to unregister a codec search function, so we just # ensure we render this one fairly harmless after the test # case finishes by using the test case repr as the codec name # The codecs module normalizes codec names, although this doesn't # appear to be formally documented... # We also make sure we use a truly unique id for the custom codec # to avoid issues with the codec cache when running these tests # multiple times (e.g. when hunting for refleaks) See bpo-22166 which fixed memory leaks in test_codecs. In 2011, a Python user requested the function https://mail.python.org/pipermail/python-dev/2011-September/113588.html Marc-Andre Lemburg explained: "There is no API to unregister a codec search function, since deregistration would break the codec cache used by the registry to speedup codec lookup." One simple solution would be to clear the cache (PyInterpreterState.codec_search_cache) when codecs.unregister() removes a search function. I expect that calling unregister() is an uncommon operation, so the performance is not a blocker issue. ---------- components: Library (Lib), Unicode messages: 377377 nosy: ezio.melotti, vstinner priority: normal severity: normal status: open title: Add codecs.unregister() to unregister a codec search function versions: Python 3.10 _______________________________________ Python tracker <rep...@bugs.python.org> <https://bugs.python.org/issue41842> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
