fix: NINJA envvar

Signed-off-by: Henry Schreiner <[email protected]>

Author: henryiii

Diff for: mesonpy/__init__.py

@@ -74,8 +74,7 @@
     'reset': '\33[0m',
 }
 _NO_COLORS = {color: '' for color in _COLORS}
-_NINJA_REQUIRED_VERSION = (1, 8, 2)
-_NINJA_REQUIRED_VERSION_STR = '.'.join(str(v) for v in _NINJA_REQUIRED_VERSION)
+_NINJA_REQUIRED_VERSION = '1.8.2'
 
 
 class _depstr:
@@ -84,7 +83,7 @@ class _depstr:
     """
     patchelf = 'patchelf >= 0.11.0'
     wheel = 'wheel >= 0.36.0'  # noqa: F811
-    ninja = f'ninja >= {_NINJA_REQUIRED_VERSION_STR}'
+    ninja = f'ninja >= {_NINJA_REQUIRED_VERSION}'
 
 
 def _init_colors() -> Dict[str, str]:
@@ -560,6 +559,12 @@ def __init__(
         self._build_dir = pathlib.Path(build_dir).absolute() if build_dir else (self._working_dir / 'build')
         self._install_dir = self._working_dir / 'install'
         self._meson_native_file = self._source_dir / '.mesonpy-native-file.ini'
+        self._env = os.environ.copy()
+
+        # prepare environment
+        ninja_path = _env_ninja_command()
+        if ninja_path is not None:
+            self._env.setdefault('NINJA', str(ninja_path))
 
         # load config -- PEP 621 support is optional
         self._config = tomllib.loads(self._source_dir.joinpath('pyproject.toml').read_text())
@@ -614,7 +619,7 @@ def __init__(
     def _proc(self, *args: str) -> None:
         """Invoke a subprocess."""
         print('{cyan}{bold}+ {}{reset}'.format(' '.join(args), **_STYLES))
-        subprocess.check_call(list(args))
+        subprocess.check_call(list(args), env=self._env)
 
     def _meson(self, *args: str) -> None:
         """Invoke Meson."""
@@ -891,7 +896,11 @@ def _project(config_settings: Optional[Dict[Any, Any]]) -> Iterator[Project]:
         yield project
 
 
-def _env_has_ninja_command() -> bool:
+def _env_ninja_command(*, version: str = _NINJA_REQUIRED_VERSION) -> Optional[pathlib.Path]:
+    """
+    Returns the path to ninja, or None if no ninja found.
+    """
+    required_version = tuple(int(v) for v in version.split('.'))
     env_ninja = os.environ.get('NINJA', None)
     ninja_candidates = [env_ninja] if env_ninja else ['ninja', 'ninja-build', 'samu']
     for ninja in ninja_candidates:
@@ -905,18 +914,17 @@ def _env_has_ninja_command() -> bool:
             candidate_version = tuple(int(x) for x in result.stdout.split('.')[:3])
         except ValueError:
             continue
-        if candidate_version < _NINJA_REQUIRED_VERSION:
+        if candidate_version < required_version:
             continue
-        return True
+        return pathlib.Path(ninja_path)
 
-    return False
+    return None
 
 
 def get_requires_for_build_sdist(
     config_settings: Optional[Dict[str, str]] = None,
 ) -> List[str]:
-
-    return [] if _env_has_ninja_command() else [_depstr.ninja]
+    return [_depstr.ninja] if _env_ninja_command() is None else []
 
 
 def build_sdist(
@@ -935,7 +943,7 @@ def get_requires_for_build_wheel(
 ) -> List[str]:
     dependencies = [_depstr.wheel]
 
-    if not _env_has_ninja_command():
+    if _env_ninja_command() is None:
         dependencies.append(_depstr.ninja)
 
     if sys.platform.startswith('linux'):