Provide first component of dotted path to namespace searches (#1575)

* Use first component of dotted path only in namespace searches

* Add test and catch KeyError instead of altering search strategy

astroid/interpreter/_import/util.py

@@ -18,17 +18,18 @@ def is_namespace(modname: str) -> bool:
  # That's unacceptable here, so we fallback to _find_spec_from_path(), which does
  # not, but requires instead that each single parent ('astroid', 'nodes', etc.)
  # be specced from left to right.
- processed_components = []
- last_parent = None
- for component in modname.split("."):
- processed_components.append(component)
- working_modname = ".".join(processed_components)
+ components = modname.split(".")
+ for i in range(1, len(components) + 1):
+ working_modname = ".".join(components[:i])
  try:
- found_spec = _find_spec_from_path(working_modname, last_parent)
+ # Search under the highest package name
+ # Only relevant if package not already on sys.path
+ # See https:/python/cpython/issues/89754 for reasoning
+ # Otherwise can raise bare KeyError: https:/python/cpython/issues/93334
+ found_spec = _find_spec_from_path(working_modname, components[0])
  except ValueError:
  # executed .pth files may not have __spec__
  return True
- last_parent = working_modname
 
  if found_spec is None:
  return False

tests/testdata/python3/data/parent_of_homonym/doc/README.md

@@ -0,0 +1,2 @@
+This submodule should have the same name as a directory in the root of the project that
+is _NOT_ a python module. For this reason, it's currently called "doc".

tests/unittest_manager.py

@@ -120,6 +120,11 @@ def test_identify_old_namespace_package_protocol(self) -> None:
  util.is_namespace("tests.testdata.python3.data.path_pkg_resources_1")
  )
 
+ def test_submodule_homonym_with_non_module(self) -> None:
+ self.assertFalse(
+ util.is_namespace("tests.testdata.python3.data.parent_of_homonym.doc")
+ )
+
  def test_implicit_namespace_package(self) -> None:
  data_dir = os.path.dirname(resources.find("data/namespace_pep_420"))
  contribute = os.path.join(data_dir, "contribute_to_namespace")