New submission from __starrify__ <pen...@libstarrify.so>:
Currently (as of df69e75) it checks only the initial letter (via `mode.startswith`) of "mode" in gzip.GzipFile.__init__. See also: https://github.com/python/cpython/blob/df69e75/Lib/gzip.py#L183 I'd personally suggest that it takes also "+" into consideration, which shall be regarded as writable. One common (hm.. at least I've observed more than once recently) case where people may make mistakes is to use a tempfile.NamedTemporaryFile as the file object without specifying explicitly a mode, while expecting the GzipFile to be writable. A quick example (in Python 3.7.11): ``` >>> import tempfile >>> tempfile.NamedTemporaryFile().mode 'rb+' >>> import gzip >>> gzip.GzipFile(fileobj=tempfile.NamedTemporaryFile(mode='rb+')).writable() False >>> gzip.GzipFile(fileobj=tempfile.NamedTemporaryFile(mode='wb')).writable() True ``` Unfortunately this change request may be backward-incompatible, since previously modes like "r+b" have been treated as read-only. See also: https://github.com/python/cpython/blob/df69e75/Lib/test/test_gzip.py#L464 ---------- components: Library (Lib) messages: 353244 nosy: __starrify__ priority: normal severity: normal status: open title: "+" ignored when determining file mode in gzip.GzipFile.__init__ type: enhancement versions: Python 3.9 _______________________________________ Python tracker <rep...@bugs.python.org> <https://bugs.python.org/issue38281> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
