ZipReadFS claims to be case-insensitive but probably shouldn't

[dcoshea]

The fix for issue #6 enables something like my test case in that issue to work - specifying paths within a .zip file works regardless of the case of the path within the .zip file, at least when I provide the path using the same case as appears in the .zip file:

>>> zip.listdir("/testdir")
['lower', 'Mixed', 'UPPER']
>>> zip.open('/testdir/lower').read()
'lower\n'
>>> zip.open('/testdir/Mixed').read()
'mixed\n'
>>> zip.open('/testdir/UPPER').read()
'upper\n'

However, it doesn't work if I specify a path in the wrong case:

>>> zip.open('/testdir/upper').read()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "[...]/site-packages/fs/base.py", line 1224, in open
    bin_file = self.openbin(path, mode=bin_mode, buffering=buffering)
  File "[...]/site-packages/fs/archive/zipfs/__init__.py", line 217, in openbin
    raise errors.ResourceNotFound(path)
fs.errors.ResourceNotFound: resource '/testdir/upper' not found

despite this claim that the filesystem is not case-sensitive:

>>> zip.getmeta()["case_insensitive"]
True

The Info-ZIP zip manual page suggests that .zip files are in fact case-sensitive:

it is possible the archive came from a system where case does matter and the archive could include both Bar and bar as separate files in the archive.

The Python 3.6.13 zipfile module's documentation doesn't say anything about case, but at least in Python 3.6.8 the module seems to be similarly case-sensitive.

I think then that the bug is just that zip.getmeta()["case_insensitive"] returns True when it should return False.

Incidentally fs.zipfs.ReadZipFS which comes with PyFilesystem has the same bug. I'll try to get around to filing a bug against that package too.

[althonos]

Thanks for the report, i forgot to change this but indeed #6 has shown that Zip files were not case insensitive. I'm actually doing some work on Pyfilesystem2 at the moment including a refactoring of the _ZipExtFile to use the seeking mechanism provided by CPython instead of our hack on Python3.7+, so I'll patch this bug as the same time.

[althonos]

This will be partially fixed in PyFilesystem/pyfilesystem2#527.

[dcoshea]

Thanks very much! I actually use PyFilesystem's .zip file handling rather than fs.archive's (due to issue #3), and I found this bug by accident when trying to investigate a problem in PyFilesystem - I imported the wrong module and used the wrong class - so you fixed the bug that actually matters to me.

[althonos]

I marked TarReadFS and ZipReadFS as case-sensitive in release v0.7.3.