Cmake: popen_safe(..., errors='ignore')

[scivision]

probably something to consider making a default for mesonlib/Popen_safe() in general,
but at least for cmake/executor, using

ret = subprocess.run(..., universal_newlines=False, ...)
stdout = ret.stdout.decode(errors='ignore')

instead of Popen_safe() avoids Meson crash/traceback when a dependency(..., method: 'cmake') search goes wrong, and the compiler or Cmake feed back binary garbage not suitable for .decode() implicit in mesonlib/Popen_safe()

That is, this change allows Meson to simply note the dependency as "not found" instead of crashing Meson.

the PR turned out to be not so simple--needs to be rereviewed after

[mensinda]

We should probably remove this from 0.52.2, if this get's much more complicated.

Also, I doubt that there will be a 0.52.2 at all with 0.53.0 dev freeze 22/12, release 29/12

[scivision]

great good to know--this is worth fixing for 0.53.0

[scivision]

Actually I think the fix in cmake/executor.py is to use subprocess.run(, errors='ignore') instead of Popen_safe(), which has undesired fallback behavior not helpful for this application. There are other areas of Meson where I also did not use Popen_safe(), where I was not interested in non-UTF8/non-ASCII or other fancy things, just wanted simple text.

[mensinda]

Python 3.5 subprocess.run also does not have the errors key. It was added in 3.6 from what I can tell. I guess this would be another reason for #6297.

[scivision]

Hmm, then maybe like

ret = subprocess.run(..., universal_newlines=False)

stdout = ret.stdout.decode(errors='ignore')

[mensinda]

To be honest, I don't see the point in having the if sys.version_info >= (3, 6), since the try-catch block does basically the same thing (unless I missed something).

[scivision]

yes it was needless, it's much simpler as in edited comment