ENH: do not check extension module file name against expected suffix

[dnicolodi]

Checking that the extensions modules filenames end with a suffix accepted by the current Python interpreter assumes that the wheel being assembled is for the same Python platform. This is not true when cross-compiling. The check protects against a very unlikely occurrence and makes life harder for tools that allow cross-compiling Python wheels. Remove it.

See #321.

[rgommers]

+1 for doing this. We can either remove the check completely, or remove it when we know we're cross-compiling. Which is something that I think we anyway need to know - we already do know on macOS, and outside of macOS it's a matter of checking for a cross file in config-settings.

[FFY00]

We can either remove the check completely, or remove it when we know we're cross-compiling.

I'd prefeer if we just kept the check, but limited to when we are not cross-compiling.

[dnicolodi]

I added the check, but I came to the conclusion that it is not a good idea. Among other things, it prevents installing a data file in {platlib}, which I think is an acceptable thing to do.

[FFY00]

it prevents installing a data file in {platlib}

A data file that ends with .so... but yeah, that's reasonable.

[dnicolodi]

A data file that ends with .so... but yeah, that's reasonable.

Oh, you are right. I forgot about the double extension check. However, if someone goes into the trouble of putting something that looks like a Python extension module for the wront interpreter version in {platlib} they win the right of having thing break if they try to import it.

[doronbehar]

Thanks @rgommers for linking this PR from #321, I missed it somehow when browsing #321. While thinking my self how can I fix this issue with a patch applied upon the 0.12.1 tag, I noticed a few things which perhaps were missing from this PR?

First of all (easy), the docstring wasn't trimmed:

diff --git i/mesonpy/__init__.py w/mesonpy/__init__.py
index 78db5d8..5832d4e 100644
--- i/mesonpy/__init__.py
+++ w/mesonpy/__init__.py
@@ -341,10 +341,6 @@ class _WheelBuilder():
         and .so on other platforms) and, if they all share the same
         PEP 3149 filename stable ABI tag, return it.
 
-        All files that look like extension modules are verified to
-        have a file name compatibel with what is expected by the
-        Python interpreter. An exception is raised otherwise.
-
         Other files are ignored.
 
         """

Secondly, this if:

meson-python/mesonpy/__init__.py

Lines 351 to 355 in 961fb56

	soext = sorted(_EXTENSION_SUFFIXES, key=len)[0]
	abis = []
	for path, _ in self._wheel_files['platlib']:
	if path.suffix == soext:

Doesn't assume that the "Host" machine and "Build" / "Target" machine have the same "shared object" file extension (so usually)? Maybe this is too much to ask - that meson-python will support cross compiling from Linux to Windows for example, but perhaps at least a comment above this conditional would be nice.

[rgommers]

Good points, thanks @doronbehar.

Maybe this is too much to ask - that meson-python will support cross compiling from Linux to Windows for example, but perhaps at least a comment above this conditional would be nice.

It's not too much to ask - I'm hoping we can make that work at some point. But in practice it's not that common to do that, so it may take a while before we need to work around this one. In the meantime, there's some bigger cross-compilation fish to fry, in Meson itself and in dealing with sysconfig and other things that everyone has to monkeypatch right now.

[doronbehar]

Here's a small fixup PR with docstring and a comment to that condition: #349