ENH: remove the need for a working directory

Currently a Project has an associated a temporary working directory
containing the build directory (unless the user specifies another one
via configuration options) and the install directory for the meson
project.  The code can be simplified assigning to the project a build
directory and always using a temporary install directory.

Note that currently all files are copied into the Python wheel from
the source or build directory, thus running meson install into a
destination directory is not that useful. This will be fixes in later
commits.

mesonpy/__init__.py

@@ -489,30 +489,33 @@ def _wheel_write_metadata(self, whl: mesonpy._wheelfile.WheelFile) -> None:
     def build(self, directory: Path) -> pathlib.Path:
         # ensure project is built
         self._project.build()
-        # install the project
-        self._project.install()
 
-        wheel_file = pathlib.Path(directory, f'{self.name}.whl')
-        with mesonpy._wheelfile.WheelFile(wheel_file, 'w') as whl:
-            self._wheel_write_metadata(whl)
+        # install project in temporary destination directory
+        with tempfile.TemporaryDirectory() as destdir:
+            self._project.install(destdir)
 
-            with mesonpy._util.cli_counter(sum(len(x) for x in self._wheel_files.values())) as counter:
+            wheel_file = pathlib.Path(directory, f'{self.name}.whl')
 
-                root = 'purelib' if self.is_pure else 'platlib'
+            with mesonpy._wheelfile.WheelFile(wheel_file, 'w') as whl:
+                self._wheel_write_metadata(whl)
 
-                for path, entries in self._wheel_files.items():
-                    for dst, src in entries:
-                        counter.update(src)
+                with mesonpy._util.cli_counter(sum(len(x) for x in self._wheel_files.values())) as counter:
 
-                        if path == root:
-                            pass
-                        elif path == 'mesonpy-libs':
-                            # custom installation path for bundled libraries
-                            dst = pathlib.Path(f'.{self._project.name}.mesonpy.libs', dst)
-                        else:
-                            dst = pathlib.Path(self.data_dir, path, dst)
+                    root = 'purelib' if self.is_pure else 'platlib'
+
+                    for path, entries in self._wheel_files.items():
+                        for dst, src in entries:
+                            counter.update(src)
 
-                        self._install_path(whl, src, dst)
+                            if path == root:
+                                pass
+                            elif path == 'mesonpy-libs':
+                                # custom installation path for bundled libraries
+                                dst = pathlib.Path(f'.{self._project.name}.mesonpy.libs', dst)
+                            else:
+                                dst = pathlib.Path(self.data_dir, path, dst)
+
+                            self._install_path(whl, src, dst)
 
         return wheel_file
 
@@ -628,16 +631,13 @@ 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)
@@ -651,7 +651,6 @@ 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)
 
         # setuptools-like ARCHFLAGS environment variable support
         if sysconfig.get_platform().startswith('macosx-'):
@@ -805,24 +804,11 @@ def build(self) -> None:
         """Build the Meson project."""
         self._run(self._build_command)
 
-    def install(self) -> None:
+    def install(self, destdir: Path) -> None:
         """Install the Meson project."""
-        destdir = os.fspath(self._install_dir)
+        destdir = os.fspath(destdir)
         self._run(['meson', 'install', '--quiet', '--no-rebuild', '--destdir', destdir, *self._meson_args['install']])
 
-    @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)
-
     @functools.lru_cache()
     def _info(self, name: str) -> Dict[str, Any]:
         """Read info from meson-info directory."""
@@ -974,18 +960,19 @@ 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, ...]:

tests/test_editable.py

@@ -61,13 +61,12 @@ def test_collect(package_complex):
 def test_mesonpy_meta_finder(package_complex, tmp_path):
     # build a package in a temporary directory
     mesonpy.Project(package_complex, tmp_path)
-    build_path = tmp_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_path), ['ninja'])
 
     # check repr
-    assert repr(finder) == f'MesonpyMetaFinder({str(build_path)!r})'
+    assert repr(finder) == f'MesonpyMetaFinder({str(tmp_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_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_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_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_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_options.py

@@ -32,6 +32,6 @@ def test_ndebug(package_purelib_and_platlib, tmp_path, args, expected):
             # compile a C source file (the trailing ^ is used to
             # specify the target that is the first output of the rule
             # containing the specified source file).
-            ['ninja', '-C', os.fspath(project._build_dir), '-t', 'commands', '../../plat.c^'],
+            ['ninja', '-C', os.fspath(project._build_dir), '-t', 'commands', '../plat.c^'],
             stdout=subprocess.PIPE, check=True).stdout
         assert (b'-DNDEBUG' in command) == expected

tests/test_project.py

@@ -30,7 +30,7 @@
     ]
 )
 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('-', '_')
 
 
@@ -42,21 +42,21 @@ 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
 
 
@@ -205,7 +205,7 @@ 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'
@@ -214,7 +214,7 @@ 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_wheel.py

@@ -229,7 +229,7 @@ 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',
@@ -239,7 +239,7 @@ def test_top_level_modules(package_module_types):
 
 def test_purelib_platlib_split(package_purelib_platlib_split, tmp_path):
     with pytest.raises(mesonpy.BuildError, match='The purelib-platlib-split package is split'):
-        with mesonpy.Project.with_temp_working_dir() as project:
+        with mesonpy._project() as project:
             project.wheel(tmp_path)