ENH: respect exclude_dirs and exclude_files in editable installs

Add support for the exclude_dirs and exclude_files arguments of
install_subdir() Meson function. Extend editable install tests to
cover this functionality and a more complex package layout.

mesonpy/_editable.py

@@ -222,13 +222,21 @@ def get(self, key: Union[str, Tuple[str, ...]]) -> Optional[Union[Node, str]]:
         return dict.get(node, key)
 
 
-def walk(root: str, path: str = '') -> Iterator[pathlib.Path]:
-    with os.scandir(os.path.join(root, path)) as entries:
-        for entry in entries:
-            if entry.is_dir():
-                yield from walk(root, os.path.join(path, entry.name))
-            else:
-                yield pathlib.Path(path, entry.name)
+def walk(src: str, exclude_files: Set[str], exclude_dirs: Set[str]) -> Iterator[str]:
+    for root, dirnames, filenames in os.walk(src):
+        for name in dirnames.copy():
+            dirsrc = os.path.join(root, name)
+            relpath = os.path.relpath(dirsrc, src)
+            if relpath in exclude_dirs:
+                dirnames.remove(name)
+            # sort to process directories determninistically
+            dirnames.sort()
+        for name in sorted(filenames):
+            filesrc = os.path.join(root, name)
+            relpath = os.path.relpath(filesrc, src)
+            if relpath in exclude_files:
+                continue
+            yield relpath
 
 
 def collect(install_plan: Dict[str, Dict[str, Any]]) -> Node:
@@ -238,8 +246,10 @@ def collect(install_plan: Dict[str, Dict[str, Any]]) -> Node:
             path = pathlib.Path(target['destination'])
             if path.parts[0] in {'{py_platlib}', '{py_purelib}'}:
                 if key == 'install_subdirs' and os.path.isdir(src):
-                    for entry in walk(src):
-                        tree[(*path.parts[1:], *entry.parts)] = os.path.join(src, *entry.parts)
+                    exclude_files = {os.path.normpath(x) for x in target.get('exclude_files', [])}
+                    exclude_dirs = {os.path.normpath(x) for x in target.get('exclude_dirs', [])}
+                    for entry in walk(src, exclude_files, exclude_dirs):
+                        tree[(*path.parts[1:], *entry.split(os.sep))] = os.path.join(src, entry)
                 else:
                     tree[path.parts[1:]] = src
     return tree

tests/packages/complex/meson.build

@@ -15,13 +15,36 @@ endif
 
 py = import('python').find_installation()
 
-py.install_sources('move.py', subdir: 'complex/more', pure: false)
-
-install_data('foo.py', rename: 'bar.py', install_dir: py.get_install_dir(pure: false) / 'complex')
-
-install_subdir('complex', install_dir: py.get_install_dir(pure: false))
-
-py.extension_module('test', 'test.pyx', install: true, subdir: 'complex')
-py.extension_module('baz', 'complex/more/baz.pyx', install: true, subdir: 'complex/more')
+py.install_sources(
+    'move.py',
+    subdir: 'complex/more',
+    pure: false,
+)
+
+install_data(
+    'foo.py',
+    rename: 'bar.py',
+    install_dir: py.get_install_dir(pure: false) / 'complex',
+)
+
+install_subdir(
+    'complex',
+    install_dir: py.get_install_dir(pure: false),
+    exclude_files: ['more/meson.build', 'more/baz.pyx'],
+)
+
+py.extension_module(
+    'test',
+    'test.pyx',
+    install: true,
+    subdir: 'complex',
+)
+
+py.extension_module(
+    'baz',
+    'complex/more/baz.pyx',
+    install: true,
+    subdir: 'complex/more',
+)
 
 subdir('complex/more')

tests/test_editable.py

@@ -17,12 +17,14 @@
 
 
 def test_walk(package_complex):
-    entries = set(_editable.walk(os.fspath(package_complex / 'complex')))
-    assert entries == {
+    entries = _editable.walk(
+        os.fspath(package_complex / 'complex'),
+        [os.path.normpath('more/meson.build'), os.path.normpath('more/baz.pyx')],
+        ['namespace'],
+    )
+    assert {pathlib.Path(x) for x in entries} == {
         pathlib.Path('__init__.py'),
         pathlib.Path('more/__init__.py'),
-        pathlib.Path('namespace/bar.py'),
-        pathlib.Path('namespace/foo.py')
     }