ENH: do not run 'meson install' to produce a wheel

There is no need to have the files copied in the installation
directory: they are read from the source and build trees. This removes
the concept of a Project working directory containing the installation
directory and the build directory (unless the user specifies one). A
Project now only has a source directory and a build directory. Adapt
the tests accordingly.

Author: dnicolodi

meson.build

@@ -17,7 +17,6 @@ py.install_sources(
   'mesonpy/_dylib.py',
   'mesonpy/_editable.py',
   'mesonpy/_elf.py',
-  'mesonpy/_introspection.py',
   'mesonpy/_tags.py',
   'mesonpy/_util.py',
   'mesonpy/_wheelfile.py',

mesonpy/__init__.py

@@ -48,7 +48,6 @@
 import mesonpy._compat
 import mesonpy._dylib
 import mesonpy._elf
-import mesonpy._introspection
 import mesonpy._tags
 import mesonpy._util
 import mesonpy._wheelfile
@@ -628,16 +627,13 @@ class Project():
     def __init__(
         self,
         source_dir: Path,
-        working_dir: Path,
-        build_dir: Optional[Path] = None,
+        build_dir: Path,
         meson_args: Optional[MesonArgs] = None,
         editable_verbose: bool = False,
     ) -> None:
         self._source_dir = pathlib.Path(source_dir).absolute()
-        self._working_dir = pathlib.Path(working_dir).absolute()
-        self._build_dir = pathlib.Path(build_dir).absolute() if build_dir else (self._working_dir / 'build')
+        self._build_dir = pathlib.Path(build_dir).absolute()
         self._editable_verbose = editable_verbose
-        self._install_dir = self._working_dir / 'install'
         self._meson_native_file = self._build_dir / 'meson-python-native-file.ini'
         self._meson_cross_file = self._build_dir / 'meson-python-cross-file.ini'
         self._meson_args: MesonArgs = collections.defaultdict(list)
@@ -692,7 +688,6 @@ def __init__(
 
         # make sure the build dir exists
         self._build_dir.mkdir(exist_ok=True, parents=True)
-        self._install_dir.mkdir(exist_ok=True, parents=True)
 
         # write the native file
         native_file_data = textwrap.dedent(f'''
@@ -737,26 +732,15 @@ def _run(self, cmd: Sequence[str]) -> None:
 
     def _configure(self, reconfigure: bool = False) -> None:
         """Configure Meson project."""
-        sys_paths = mesonpy._introspection.SYSCONFIG_PATHS
         setup_args = [
-            f'--prefix={sys.base_prefix}',
             os.fspath(self._source_dir),
             os.fspath(self._build_dir),
             f'--native-file={os.fspath(self._meson_native_file)}',
-            # TODO: Allow configuring these arguments
+            # default arguments
             '-Ddebug=false',
             '-Db_ndebug=if-release',
             '-Doptimization=2',
-
-            # XXX: This should not be needed, but Meson is using the wrong paths
-            #      in some scenarios, like on macOS.
-            #      https://github.com/mesonbuild/meson-python/pull/87#discussion_r1047041306
-            '--python.purelibdir',
-            sys_paths['purelib'],
-            '--python.platlibdir',
-            sys_paths['platlib'],
-
-            # user args
+            # user arguments
             *self._meson_args['setup'],
         ]
         if reconfigure:
@@ -795,38 +779,11 @@ def _wheel_builder(self) -> _WheelBuilder:
             self._install_plan,
         )
 
-    def build_commands(self, install_dir: Optional[pathlib.Path] = None) -> Sequence[Sequence[str]]:
-        assert self._ninja is not None  # help mypy out
-        return (
-            (self._ninja, *self._meson_args['compile'],),
-            (
-                'meson',
-                'install',
-                '--only-changed',
-                '--destdir',
-                os.fspath(install_dir or self._install_dir),
-                *self._meson_args['install'],
-            ),
-        )
-
     @functools.lru_cache(maxsize=None)
     def build(self) -> None:
-        """Trigger the Meson build."""
-        for cmd in self.build_commands():
-            self._run(cmd)
-
-    @classmethod
-    @contextlib.contextmanager
-    def with_temp_working_dir(
-        cls,
-        source_dir: Path = os.path.curdir,
-        build_dir: Optional[Path] = None,
-        meson_args: Optional[MesonArgs] = None,
-        editable_verbose: bool = False,
-    ) -> Iterator[Project]:
-        """Creates a project instance pointing to a temporary working directory."""
-        with tempfile.TemporaryDirectory(prefix='.mesonpy-', dir=os.fspath(source_dir)) as tmpdir:
-            yield cls(source_dir, tmpdir, build_dir, meson_args, editable_verbose)
+        """Build Meson project."""
+        assert self._ninja is not None  # help mypy
+        self._run([self._ninja, *self._meson_args['compile']])
 
     @functools.lru_cache()
     def _info(self, name: str) -> Dict[str, Any]:
@@ -975,18 +932,19 @@ def editable(self, directory: Path) -> pathlib.Path:
 
 
 @contextlib.contextmanager
-def _project(config_settings: Optional[Dict[Any, Any]]) -> Iterator[Project]:
+def _project(config_settings: Optional[Dict[Any, Any]] = None) -> Iterator[Project]:
     """Create the project given the given config settings."""
 
     settings = _validate_config_settings(config_settings or {})
-    meson_args = {name: settings.get(f'{name}-args', []) for name in _MESON_ARGS_KEYS}
-
-    with Project.with_temp_working_dir(
-            build_dir=settings.get('builddir'),
-            meson_args=typing.cast(MesonArgs, meson_args),
-            editable_verbose=bool(settings.get('editable-verbose'))
-    ) as project:
-        yield project
+    meson_args = typing.cast(MesonArgs, {name: settings.get(f'{name}-args', []) for name in _MESON_ARGS_KEYS})
+    source_dir = os.path.curdir
+    build_dir = settings.get('builddir')
+    editable_verbose = bool(settings.get('editable-verbose'))
+
+    with contextlib.ExitStack() as ctx:
+        if build_dir is None:
+            build_dir = ctx.enter_context(tempfile.TemporaryDirectory(prefix='.mesonpy-', dir=source_dir))
+        yield Project(source_dir, build_dir, meson_args, editable_verbose)
 
 
 def _parse_version_string(string: str) -> Tuple[int, ...]:

mesonpy/_introspection.py

@@ -61,13 +61,12 @@ def test_collect(package_complex):
 def test_mesonpy_meta_finder(package_complex, tmp_build_path):
     # build a package in a temporary directory
     mesonpy.Project(package_complex, tmp_build_path)
-    build_path = tmp_build_path / 'build'
 
     # point the meta finder to the build directory
-    finder = _editable.MesonpyMetaFinder({'complex'}, os.fspath(build_path), ['ninja'])
+    finder = _editable.MesonpyMetaFinder({'complex'}, os.fspath(tmp_build_path), ['ninja'])
 
     # check repr
-    assert repr(finder) == f'MesonpyMetaFinder({str(build_path)!r})'
+    assert repr(finder) == f'MesonpyMetaFinder({str(tmp_build_path)!r})'
 
     # verify that we can look up a pure module in the source directory
     spec = finder.find_spec('complex')
@@ -79,7 +78,7 @@ def test_mesonpy_meta_finder(package_complex, tmp_build_path):
     spec = finder.find_spec('complex.test')
     assert spec.name == 'complex.test'
     assert isinstance(spec.loader, _editable.ExtensionFileLoader)
-    assert spec.origin == os.fspath(build_path / f'test{EXT_SUFFIX}')
+    assert spec.origin == os.fspath(tmp_build_path / f'test{EXT_SUFFIX}')
 
     try:
         # install the finder in the meta path
@@ -89,7 +88,7 @@ def test_mesonpy_meta_finder(package_complex, tmp_build_path):
         assert complex.__spec__.origin == os.fspath(package_complex / 'complex/__init__.py')
         assert complex.__file__ == os.fspath(package_complex / 'complex/__init__.py')
         import complex.test
-        assert complex.test.__spec__.origin == os.fspath(build_path / f'test{EXT_SUFFIX}')
+        assert complex.test.__spec__.origin == os.fspath(tmp_build_path / f'test{EXT_SUFFIX}')
         assert complex.test.answer() == 42
         import complex.namespace.foo
         assert complex.namespace.foo.__spec__.origin == os.fspath(package_complex / 'complex/namespace/foo.py')
@@ -128,7 +127,7 @@ def test_resources(tmp_path):
     mesonpy.Project(package_path, tmp_path)
 
     # point the meta finder to the build directory
-    finder = _editable.MesonpyMetaFinder({'simple'}, os.fspath(tmp_path / 'build'), ['ninja'])
+    finder = _editable.MesonpyMetaFinder({'simple'}, os.fspath(tmp_path), ['ninja'])
 
     # verify that we can look up resources
     spec = finder.find_spec('simple')
@@ -147,7 +146,7 @@ def test_importlib_resources(tmp_path):
     mesonpy.Project(package_path, tmp_path)
 
     # point the meta finder to the build directory
-    finder = _editable.MesonpyMetaFinder({'simple'}, os.fspath(tmp_path / 'build'), ['ninja'])
+    finder = _editable.MesonpyMetaFinder({'simple'}, os.fspath(tmp_path), ['ninja'])
 
     try:
         # install the finder in the meta path

tests/test_editable.py

@@ -28,7 +28,7 @@
     ]
 )
 def test_name(package):
-    with chdir(package_dir / package), mesonpy.Project.with_temp_working_dir() as project:
+    with chdir(package_dir / package), mesonpy._project() as project:
         assert project.name == package.replace('-', '_')
 
 
@@ -40,21 +40,21 @@ def test_name(package):
     ]
 )
 def test_version(package):
-    with chdir(package_dir / package), mesonpy.Project.with_temp_working_dir() as project:
+    with chdir(package_dir / package), mesonpy._project() as project:
         assert project.version == '1.0.0'
 
 
 def test_unsupported_dynamic(package_unsupported_dynamic):
     with pytest.raises(mesonpy.MesonBuilderError, match='Unsupported dynamic fields: "dependencies"'):
-        with mesonpy.Project.with_temp_working_dir():
+        with mesonpy._project():
             pass
 
 
 def test_unsupported_python_version(package_unsupported_python_version):
     with pytest.raises(mesonpy.MesonBuilderError, match=(
         f'Unsupported Python version {platform.python_version()}, expected ==1.0.0'
     )):
-        with mesonpy.Project.with_temp_working_dir():
+        with mesonpy._project():
             pass
 
 
@@ -76,7 +76,7 @@ def last_two_meson_args():
         'dist-args': ('cli-dist',),
         'setup-args': ('cli-setup',),
         'compile-args': ('cli-compile',),
-        'install-args': ('cli-install',),
+        'install-args': ('cli-install',), # 'meson install' is not called thus we cannot test this
     }
 
     mesonpy.build_sdist(tmp_path, config_settings)
@@ -86,10 +86,9 @@ def last_two_meson_args():
         # sdist: calls to 'meson setup' and 'meson dist'
         ('config-setup', 'cli-setup'),
         ('config-dist', 'cli-dist'),
-        # wheel: calls to 'meson setup', 'meson compile', and 'meson install'
+        # wheel: calls to 'meson setup' and 'ninja'
         ('config-setup', 'cli-setup'),
         ('config-compile', 'cli-compile'),
-        ('config-install', 'cli-install'),
     ]
 
 
@@ -174,7 +173,7 @@ def test_invalid_build_dir(package_pure, tmp_path, mocker):
     meson.reset_mock()
 
     # corrupting the build direcory setup is run again
-    tmp_path.joinpath('build/meson-private/coredata.dat').unlink()
+    tmp_path.joinpath('meson-private/coredata.dat').unlink()
     project = mesonpy.Project(package_pure, tmp_path)
     assert len(meson.call_args_list) == 1
     assert meson.call_args_list[0].args[1][1] == 'setup'
@@ -183,7 +182,7 @@ def test_invalid_build_dir(package_pure, tmp_path, mocker):
     meson.reset_mock()
 
     # removing the build directory things should still work
-    shutil.rmtree(tmp_path.joinpath('build'))
+    shutil.rmtree(tmp_path)
     project = mesonpy.Project(package_pure, tmp_path)
     assert len(meson.call_args_list) == 1
     assert meson.call_args_list[0].args[1][1] == 'setup'

tests/test_project.py

@@ -232,7 +232,7 @@ def test_entrypoints(wheel_full_metadata):
 
 
 def test_top_level_modules(package_module_types):
-    with mesonpy.Project.with_temp_working_dir() as project:
+    with mesonpy._project() as project:
         assert set(project._wheel_builder.top_level_modules) == {
             'file',
             'package',