I am currently fighting a curious problem in using zlib from Python: Decompression completes but sometimes the resulting output does not match a sha224 hash of the expected output.

I deployed a zlib 1.2.5 with our PyInstaller output but the problem persists. I would like to check that the program is actually using the right zlib version.

zlib provides the function zlibVersion to access the actual run time version. The attached patch exposes this function from the zlib module. I also added a unit test to check that the function is there and the output matches ZLIB_VERSION (which should match on the build machine).

Good idea, and thanks for posting a patch! This is a new feature, so 3.3-only. Also, you'll need to update the docs (Doc/library/zlib.rst, presumably) to add the new module method/attribute (with a suitable "versionadded" tag).

Nitpicking:
- "zlibVersion" isn't PEP8-compliant
- semantically it should probably be a module-level attribute, rather than a method; after all it's kind of a constant; perhaps ZLIB_RUNTIME_VERSION?

Also, I see that ZLIB_VERSION itself isn't documented, it would be nice to have a separate patch to fix that.

Here is an updated patch:

 * Function zlibVersion() replaced by module-level constant ZLIB_RUNTIME_VERSION
 * Added documentation (with versionadded: 3.3)

Documentation for ZLIB_VERSION.

I just notice that it makes no sense to add the version info to that section. Feel free to move the two snippets.

I added a versionadded tag here as well (ZLIB_VERSION was already in Python 1.5). Is there any old release for that versionadded tags should be removed?

New changeset b21d1de6d78e by Nadeem Vawda in branch 'default':
Issue #12306: Add ZLIB_RUNTIME_VERSION to the zlib module.
http://hg.python.org/cpython/rev/b21d1de6d78e

I've committed your patches. I took the liberty of removing the
"versionadded" tag for ZLIB_VERSION; I don't think many people will need
to worry about compatibility with Python 1.5 ;-)

Once again, thanks for the patches!