BUG: empty __spec__.submodule_search_locations and __path__ values for editable packages

mesonpy/_editable.py

@@ -183,7 +183,13 @@ def build_module_spec(cls: type, name: str, path: str, tree: Optional[Node]) ->
     spec = importlib.machinery.ModuleSpec(name, loader, origin=path)
     spec.has_location = True
     if loader.is_package(name):
-        spec.submodule_search_locations = []
+        spec.submodule_search_locations = [os.path.dirname(path)]
+        if tree is not None:
+            for submodule_node in tree.values():
+                if isinstance(submodule_node, str):
+                    parent_folder = os.path.dirname(submodule_node)
+                    if parent_folder not in spec.submodule_search_locations:
+                        spec.submodule_search_locations.append(parent_folder)
     return spec
 
 

tests/test_editable.py

@@ -4,6 +4,7 @@
 
 import os
 import pathlib
+import pkgutil
 import sys
 
 import pytest
@@ -86,10 +87,23 @@ def test_mesonpy_meta_finder(package_complex, tmp_path):
         # verify that we can import the modules
         import complex
         assert complex.__spec__.origin == os.fspath(package_complex / 'complex/__init__.py')
-        assert complex.__file__ == os.fspath(package_complex / 'complex/__init__.py')
+        assert complex.__spec__.submodule_search_locations == [
+            os.fspath(package_complex / 'complex'),
+            str(tmp_path),
+        ]
+        assert complex.__file__ == complex.__spec__.origin
+        assert complex.__path__ == complex.__spec__.submodule_search_locations
         import complex.test
         assert complex.test.__spec__.origin == os.fspath(tmp_path / f'test{EXT_SUFFIX}')
+        assert complex.test.__file__ == complex.test.__spec__.origin
+        assert complex.test.__spec__.submodule_search_locations is None
+        assert not hasattr(complex.test, '__path__')
         assert complex.test.answer() == 42
+        import complex.more
+        assert complex.more.__spec__.origin == os.fspath(package_complex / 'complex/more/__init__.py')
+        assert complex.more.__spec__.submodule_search_locations == [os.fspath(package_complex / 'complex/more')]
+        assert complex.more.__file__ == complex.more.__spec__.origin
+        assert complex.more.__path__ == complex.more.__spec__.submodule_search_locations
         import complex.namespace.foo
         assert complex.namespace.foo.__spec__.origin == os.fspath(package_complex / 'complex/namespace/foo.py')
         assert complex.namespace.foo.foo() == 'foo'
@@ -98,6 +112,34 @@ def test_mesonpy_meta_finder(package_complex, tmp_path):
         del sys.meta_path[0]
 
 
+def test_walk_packages(package_complex, tmp_path):
+    # build a package in a temporary directory
+    mesonpy.Project(package_complex, tmp_path)
+
+    # point the meta finder to the build directory
+    finder = _editable.MesonpyMetaFinder({'complex'}, os.fspath(tmp_path), ['ninja'])
+
+    try:
+        # install the finder in the meta path
+        sys.meta_path.insert(0, finder)
+
+        import complex
+
+        module_names = sorted(
+            module_info.name
+            for module_info in pkgutil.walk_packages(complex.__path__, prefix='complex.')
+        )
+        assert module_names == [
+            'complex.more',
+            'complex.test',
+            # XXX: should namespace packages be discovered by walk_packages?
+        ]
+
+    finally:
+        # remove finder from the meta path
+        del sys.meta_path[0]
+
+
 def test_mesonpy_traversable():
     tree = _editable.Node()
     tree[('package', '__init__.py')] = '/tmp/src/package/__init__.py'