Unhandled python exception when configuring project with MSVC backend

[brunvonlope]

Describe the bug

Meson detects VS Code but fails right after:

The Meson build system
Version: 1.3.2
Source dir: C:/msys64/home/josei/gimp-fix
Build dir: C:/msys64/home/josei/gimp-fix/_build-x64
Build type: native build
Project name: gimp
Project version: 2.99.19
Activating VS 17.9.2
Exception in thread Thread-1 (_readerthread):
Exception in thread Thread-2 (_readerthread):
Traceback (most recent call last):
Traceback (most recent call last):
  File "C:/msys64/clang64/lib/python3.11/threading.py", line 1045, in _bootstrap_inner
  File "C:/msys64/clang64/lib/python3.11/threading.py", line 1045, in _bootstrap_inner
    self.run()
    self.run()
  File "C:/msys64/clang64/lib/python3.11/threading.py", line 982, in run
  File "C:/msys64/clang64/lib/python3.11/threading.py", line 982, in run
    self._target(*self._args, **self._kwargs)
    self._target(*self._args, **self._kwargs)
  File "C:/msys64/clang64/lib/python3.11/subprocess.py", line 1597, in _readerthread
  File "C:/msys64/clang64/lib/python3.11/subprocess.py", line 1597, in _readerthread
    buffer.append(fh.read())
                  ^^^^^^^^^
  File "<frozen codecs>", line 322, in decode
UnicodeDecodeError: 'utf-8' codec can't decode byte 0xc6 in position 44: invalid continuation byte
    buffer.append(fh.read())
                  ^^^^^^^^^
  File "<frozen codecs>", line 322, in decode
UnicodeDecodeError: 'utf-8' codec can't decode byte 0x80 in position 27: invalid start byte
Traceback (most recent call last):
  File "C:/msys64/clang64/lib/python3.11/site-packages/mesonbuild/mesonmain.py", line 194, in run
    return options.run_func(options)
           ^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:/msys64/clang64/lib/python3.11/site-packages/mesonbuild/msetup.py", line 358, in run
    app.generate()
  File "C:/msys64/clang64/lib/python3.11/site-packages/mesonbuild/msetup.py", line 181, in generate
    return self._generate(env, capture, vslite_ctx)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:/msys64/clang64/lib/python3.11/site-packages/mesonbuild/msetup.py", line 203, in _generate
    intr = interpreter.Interpreter(b, user_defined_options=user_defined_options)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:/msys64/clang64/lib/python3.11/site-packages/mesonbuild/interpreter/interpreter.py", line 331, in __init__
    self.parse_project()
  File "C:/msys64/clang64/lib/python3.11/site-packages/mesonbuild/interpreterbase/interpreterbase.py", line 132, in parse_project
    self.evaluate_codeblock(self.ast, end=1)
  File "C:/msys64/clang64/lib/python3.11/site-packages/mesonbuild/interpreterbase/interpreterbase.py", line 198, in evaluate_codeblock
    raise e
  File "C:/msys64/clang64/lib/python3.11/site-packages/mesonbuild/interpreterbase/interpreterbase.py", line 190, in evaluate_codeblock
    self.evaluate_statement(cur)
  File "C:/msys64/clang64/lib/python3.11/site-packages/mesonbuild/interpreterbase/interpreterbase.py", line 204, in evaluate_statement
    return self.function_call(cur)
           ^^^^^^^^^^^^^^^^^^^^^^^
  File "C:/msys64/clang64/lib/python3.11/site-packages/mesonbuild/interpreterbase/interpreterbase.py", line 530, in function_call
    res = func(node, func_args, kwargs)
          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:/msys64/clang64/lib/python3.11/site-packages/mesonbuild/interpreterbase/decorators.py", line 260, in wrapper
    return f(*nargs, **wrapped_kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:/msys64/clang64/lib/python3.11/site-packages/mesonbuild/interpreterbase/decorators.py", line 579, in wrapper
    return f(*wrapped_args, **wrapped_kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:/msys64/clang64/lib/python3.11/site-packages/mesonbuild/interpreter/interpreter.py", line 1308, in func_project
    self.add_languages(proj_langs, True, MachineChoice.HOST)
  File "C:/msys64/clang64/lib/python3.11/site-packages/mesonbuild/interpreter/interpreter.py", line 1476, in add_languages
    success = self.add_languages_for(args, required, for_machine)
              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:/msys64/clang64/lib/python3.11/site-packages/mesonbuild/interpreter/interpreter.py", line 1519, in add_languages_for
    comp = compilers.detect_compiler_for(self.environment, lang, for_machine, skip_sanity_check)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:/msys64/clang64/lib/python3.11/site-packages/mesonbuild/compilers/detect.py", line 115, in detect_compiler_for
    comp = compiler_from_language(env, lang, for_machine)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:/msys64/clang64/lib/python3.11/site-packages/mesonbuild/compilers/detect.py", line 112, in compiler_from_language
    return lang_map[lang](env, for_machine) if lang in lang_map else None
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:/msys64/clang64/lib/python3.11/site-packages/mesonbuild/compilers/detect.py", line 614, in detect_c_compiler
    return _detect_c_or_cpp_compiler(env, 'c', for_machine)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:/msys64/clang64/lib/python3.11/site-packages/mesonbuild/compilers/detect.py", line 330, in _detect_c_or_cpp_compiler
    p, out, err = Popen_safe_logged(cmd, msg='Detecting compiler via')
                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:/msys64/clang64/lib/python3.11/site-packages/mesonbuild/utils/universal.py", line 1580, in Popen_safe_logged
    rc, out, err = p.returncode, o.strip(), e.strip()
                                 ^^^^^^^
AttributeError: 'NoneType' object has no attribute 'strip'

../meson.build:1:0: ERROR: Unhandled python exception

    This is a Meson bug and should be reported!

To Reproduce

1. Clone gimp repo;
2. Run build/windows/gitlab-ci/2_build-gimp-msys2.sh (with -Dbacked=vs).

Expected behavior
Meson auto-detects MSVC and start setup

system parameters

• Native build
• Windows 11
• Python 3.11
• Meson 1.3.2

[bruchar1]

It seems to be an encoding issue. I'm not very familiar with msys. What is your current locale? I guess msys uses the LANG environment variable.

[brunvonlope]

What is your current locale? I guess msys uses the LANG environment variable.

pt-BR (i think that it uses UTF-8). But no package is localized.

I found this setting in Mintty but i'm skeptical if it have some relevance:

[bruchar1]

I'm blind-guessing, but one thing you could try is to set PYTHONIOENCODING=utf8 environment variable.
You can probably do locale -a to display the current locale. Ensure it is a utf-8 locale.
That being said, there is probably a bug in meson.

[brunvonlope]

Just tested. Still have the same problem

[brunvonlope]

This bug can't be reproduced with .msi meson provided in the GitHub releases (exact same version: 1.4.0). Probably this only affects msys2 builds.