Output dylib file hardcoded with ".so" in filename

[yegle]

In https://github.com/Valloric/ycmd/blob/master/cpp/ycm/CMakeLists.txt#L426 it assumed that ".so" is always recognized as a valid Python C module extension. But it's not always the case. Some heavy patched Python installation may use other extensions as valid extension.

Not to argue whether it's right to remove ".so" as a valid C module extension, I think it should read supported extensions from imp.get_suffixes().

FYI here's the output on my system:

• $ /usr/bin/python -c 'import imp; print(imp.get_suffixes())'
  [('.so', 'rb', 3), ('module.so', 'rb', 3), ('.py', 'U', 1), ('.pyc', 'rb', 2)]
• $ $HOME/.gentoo/usr/bin/python2 -c 'import imp; print(imp.get_suffixes())'
  [('.bundle', 'rb', 3), ('module.bundle', 'rb', 3), ('.py', 'U', 1), ('.pyc', 'rb', 2)]
• $ $HOME/.gentoo/usr/bin/python3 -c 'import imp; print(imp.get_suffixes())'
  [('.cpython-35-darwin.bundle', 'rb', 3), ('.abi3.bundle', 'rb', 3), ('.bundle', 'rb', 3), ('.py', 'r', 1), ('.pyc', 'rb', 2)]

[vheon]

Some heavy patched Python installation may use other extensions as valid extension.

What do you mean by this? Can you elaborate?

[yegle]

@vheon I'm using Gentoo Prefix https://wiki.gentoo.org/wiki/Project:Prefix as my package manager on OS X, of which they decide to patch and remove support for .so files as valid C module suffixes.

I'm not sure about all other OS X package managers out there. Some notable examples:

• https://nixos.org/wiki/Nix_on_OS_X
• https://pkgsrc.joyent.com/install-on-osx/
• https://www.macports.org/
• http://brew.sh/

[micbou]

This issue should be reported to the Gentoo Prefix maintainers because I am sure that ycmd is not the only project assuming that .so is the default extension on OS X (and for a good reason, it's the default in the Python sources) so the Python installation from Gentoo Prefix is broken for all of these projects.

Not to argue whether it's right to remove ".so" as a valid C module extension, I think it should read supported extensions from imp.get_suffixes().

Calling imp.get_suffixes() from CMake will not be easy. We'll need the path to the Python interpreter and we can't really rely on CMake to find the right one. I don't think it's worth the trouble. Not to mention that imp.get_suffixes() is deprecated since Python 3.3 (we'll need to use importlib.machinery.EXTENSION_SUFFIXES for 3.3 and later).