[issue22163] max_wbits set incorrectly to -zlib.MAX_WBITS in tarfile, shouldn't be negative
Mark Lawrence added the comment: Is the thinking and hence the patch correct here? -- nosy: +BreamoreBoy ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue22163 ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue22163] max_wbits set incorrectly to -zlib.MAX_WBITS in tarfile, shouldn't be negative
Martin Panter added the comment: I suspect the patch is wrong and the zlib documentation needs fixing instead. See https://docs.python.org/dev/library/zlib.html#zlib.decompress for a possible explanation of the negative sign, although it would make more sense for compress() which would actually create a “gzip” header. -- assignee: - docs@python components: +Documentation nosy: +docs@python, vadmium ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue22163 ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue22163] max_wbits set incorrectly to -zlib.MAX_WBITS in tarfile, shouldn't be negative
Martin Panter added the comment: Eduardo’s patch causes many tests to fail. Abbreviated test output: $ ./python -bWall -m test -v test_tarfile == ERROR: test_compare_members (test.test_tarfile.GzipStreamReadTest) ERROR: test_empty_tarfile (test.test_tarfile.GzipStreamReadTest) ERROR: test_fileobj_regular_file (test.test_tarfile.GzipStreamReadTest) ERROR: test_ignore_zeros (test.test_tarfile.GzipStreamReadTest) ERROR: test_non_existent_tarfile (test.test_tarfile.GzipStreamReadTest) ERROR: test_null_tarfile (test.test_tarfile.GzipStreamReadTest) ERROR: test_provoke_stream_error (test.test_tarfile.GzipStreamReadTest) ERROR: test_read_through (test.test_tarfile.GzipStreamReadTest) -- tarfile.ReadError: invalid compressed data == ERROR: test_stream_padding (test.test_tarfile.GzipStreamWriteTest) -- zlib.error: Error -3 while decompressing data: invalid stored block lengths == FAIL: test_detect_file (test.test_tarfile.GzipDetectReadTest) FAIL: test_detect_fileobj (test.test_tarfile.GzipDetectReadTest) AssertionError -- Ran 387 tests in 14.216s FAILED (failures=2, errors=9, skipped=8) There is already Issue 5784 open about clarifying the “wbits” parameter, so I think we can close this as a duplicate. -- resolution: - duplicate status: open - closed superseder: - raw deflate format and zlib module ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue22163 ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue22163] max_wbits set incorrectly to -zlib.MAX_WBITS in tarfile, shouldn't be negative
Changes by Terry J. Reedy tjre...@udel.edu: -- nosy: +lars.gustaebel stage: - patch review versions: -Python 3.1, Python 3.2, Python 3.3 ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue22163 ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue22163] max_wbits set incorrectly to -zlib.MAX_WBITS in tarfile, shouldn't be negative
Changes by Antoine Pitrou pit...@free.fr: -- nosy: +serhiy.storchaka ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue22163 ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue22163] max_wbits set incorrectly to -zlib.MAX_WBITS in tarfile, shouldn't be negative
New submission from Eduardo Robles Elvira: I think I have found a small typo-bug in tarfile.py, that seems to be present in cpython upstream, which makes tarfile compression slower. The issue can be seen here, in line 415 [1] of tarfile.py: self.cmp = self.zlib.compressobj(9, self.zlib.DEFLATED, -self.zlib.MAX_WBITS, self.zlib.DEF_MEM_LEVEL, 0) The minus sign doesn't make sense to me, because zlib.MAX_WBITS is 15, and according to the documentation [2] wbits is by default 15 and This should be an integer from 8 to 15. Higher values give better compression, but use more memory. -15 is not even in range. So I guess the expected value should be the zlib default, 15. Or maybe another value, but it should at least be in range. I marked it as performance type bug as this only really affects performance. I might have gotten it all wrong and it's fine the way it is, but I thought it'd be best to report it, as it looked fishy to me. -- [1] http://hg.python.org/cpython/file/94d0e842b9ea/Lib/tarfile.py#l415 [2] https://docs.python.org/3.4/library/zlib.html#zlib.compressobj -- components: Library (Lib) files: max_wbits.patch keywords: patch messages: 225006 nosy: edulix priority: normal severity: normal status: open title: max_wbits set incorrectly to -zlib.MAX_WBITS in tarfile, shouldn't be negative type: performance versions: Python 2.7, Python 3.1, Python 3.2, Python 3.3, Python 3.4, Python 3.5 Added file: http://bugs.python.org/file36299/max_wbits.patch ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue22163 ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue22163] max_wbits set incorrectly to -zlib.MAX_WBITS in tarfile, shouldn't be negative
Changes by Serhiy Storchaka storch...@gmail.com: -- nosy: +nadeem.vawda ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue22163 ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
