shutil.make_archive makes invalid directory entries

[gumblex]

BPO	25624
Nosy	@larryhastings, @benjaminp, @tarekziade, @serhiy-storchaka
Files	storedirectory.patch storedirectory_test.patch: zipfile patch with test

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = 'https://github.com/serhiy-storchaka'
closed_at = <Date 2015-12-19.08:11:01.507>
created_at = <Date 2015-11-14.09:25:24.400>
labels = ['easy', 'type-bug', 'library', 'release-blocker']
title = 'shutil.make_archive makes invalid directory entries'
updated_at = <Date 2015-12-19.08:11:01.507>
user = 'https://bugs.python.org/gumblex'

bugs.python.org fields:

activity = <Date 2015-12-19.08:11:01.507>
actor = 'serhiy.storchaka'
assignee = 'serhiy.storchaka'
closed = True
closed_date = <Date 2015-12-19.08:11:01.507>
closer = 'serhiy.storchaka'
components = ['Library (Lib)']
creation = <Date 2015-11-14.09:25:24.400>
creator = 'gumblex'
dependencies = []
files = ['41039', '41120']
hgrepos = []
issue_num = 25624
keywords = ['patch', 'easy']
message_count = 15.0
messages = ['254647', '254648', '254649', '254650', '254651', '255054', '255084', '255097', '255098', '255124', '255128', '255135', '255137', '256054', '256720']
nosy_count = 7.0
nosy_names = ['larry', 'benjamin.peterson', 'tarek', 'SilentGhost', 'python-dev', 'serhiy.storchaka', 'gumblex']
pr_nums = []
priority = 'release blocker'
resolution = 'fixed'
stage = 'resolved'
status = 'closed'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue25624'
versions = ['Python 2.7', 'Python 3.4', 'Python 3.5', 'Python 3.6']

[gumblex]

The _make_zipfile in shutil uses ZIP_DEFLATED compression by default, and the fix introduced by bpo-24982 adds directory entries. In zipfile.ZipFile.write, directories is added as 0 file_size, 0 compress_size, regardless of the compression method. Deflate will compress an empty string as \x03\x00, thus the directory entries become incorrect.

The command line interface of zipfile is correct. Shutil can be fixed as zipfile.main. As a directory entry with compression methods other than ZIP_STORED is meaningless, zipfile.write and (maybe) zipfile.writestr should always write a ZIP_STORED header for directory entries to avoid the above problem occuring by programming mistakes.

[SilentGhost]

Can you provide a test?

[serhiy-storchaka]

Do you want to provide a patch?

[gumblex]

$ mkdir foo; touch foo/a.txt; python3 -c "import shutil; shutil.make_archive('foo', 'zip', base_dir='foo')"; unzip -t foo.zip
Archive:  foo.zip
    testing: foo/                    
  error:  invalid compressed data to inflate
    testing: foo/a.txt                OK
At least one error was detected in foo.zip.

(This affects 2.7, 3.4+)

[gumblex]

My patch for this.

[serhiy-storchaka]

Could you add a test Dingyuan? You can take test_zipfile_vs_zip in test_shutil as an example.

The patch changes both shutil and zipfile. Aren't only changes to zipfile needed?

[gumblex]

Yes, patching zipfile is enough. I wrote a test using unzip -t to check the zip. ZipFile.testzip can't detect this kind of error because zlib.decompressobj(-15) will decode b'' to b'' without errors.

[python-dev]

New changeset e7d1df56f70b by Serhiy Storchaka in branch '3.4':
Issue bpo-25624: ZipFile now always writes a ZIP_STORED header for directory
https://hg.python.org/cpython/rev/e7d1df56f70b

New changeset 0f8d426e0d0c by Serhiy Storchaka in branch '3.5':
Issue bpo-25624: ZipFile now always writes a ZIP_STORED header for directory
https://hg.python.org/cpython/rev/0f8d426e0d0c

New changeset 09ed44192995 by Serhiy Storchaka in branch 'default':
Issue bpo-25624: ZipFile now always writes a ZIP_STORED header for directory
https://hg.python.org/cpython/rev/09ed44192995

New changeset de5582c569ff by Serhiy Storchaka in branch '2.7':
Issue bpo-25624: ZipFile now always writes a ZIP_STORED header for directory
https://hg.python.org/cpython/rev/de5582c569ff

[serhiy-storchaka]

Thank you for your contribution Dingyuan.

Benjamin, I think this fix should be in 2.7.11. It was a regression in 2.7.11 that had made shutil.make_archive() unusable with the zip format.

[python-dev]

New changeset 43208b0f2535 by Benjamin Peterson in branch '2.7':
Issue bpo-25624: ZipFile now always writes a ZIP_STORED header for directory entries. Patch by Dingyuan Wang.
https://hg.python.org/cpython/rev/43208b0f2535