From 47d73b1e7787cd66ee57be676f2385d2183f78ac Mon Sep 17 00:00:00 2001
From: "Jason R. Coombs" <jaraco@jaraco.com>
Date: Tue, 20 Aug 2024 11:49:50 -0400
Subject: [PATCH 1/2] Add test capturing failure when resolving the
 MultiplexedPath for a namespace package with non-path elements in the path.

Ref #311
---
 importlib_resources/tests/test_files.py | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/importlib_resources/tests/test_files.py b/importlib_resources/tests/test_files.py
index 311581c..6fdcdef 100644
--- a/importlib_resources/tests/test_files.py
+++ b/importlib_resources/tests/test_files.py
@@ -8,6 +8,8 @@
 import importlib
 import contextlib
 
+import pytest
+
 import importlib_resources as resources
 from ..abc import Traversable
 from . import util
@@ -60,6 +62,27 @@ class OpenZipTests(FilesTests, util.ZipSetup, unittest.TestCase):
 class OpenNamespaceTests(FilesTests, util.DiskSetup, unittest.TestCase):
     MODULE = 'namespacedata01'
 
+    @pytest.mark.xfail(reason="#311")
+    def test_non_paths_in_dunder_path(self):
+        """
+        Non-path items in a namespace package's ``__path__`` are ignored.
+
+        As reported in python/importlib_resources#311, some tools
+        like Setuptools, when creating editable packages, will inject
+        non-paths into a namespace package's ``__path__``, a
+        sentinel like
+        ``__editable__.sample_namespace-1.0.finder.__path_hook__``
+        to cause the ``PathEntryFinder`` to be called when searching
+        for packages. In that case, resources should still be loadable.
+        """
+        import namespacedata01
+
+        namespacedata01.__path__.append(
+            '__editable__.sample_namespace-1.0.finder.__path_hook__'
+        )
+
+        resources.files(namespacedata01)
+
 
 class OpenNamespaceZipTests(FilesTests, util.ZipSetup, unittest.TestCase):
     ZIP_MODULE = 'namespacedata01'

From 2c145c5b1ff95290794b2cb63e5c924e1847456d Mon Sep 17 00:00:00 2001
From: "Jason R. Coombs" <jaraco@jaraco.com>
Date: Tue, 20 Aug 2024 12:11:53 -0400
Subject: [PATCH 2/2] Omit sentinel values from a namespace path.

When editable installs create sentinels, as they are not a valid directory, they're unsuitable for constructing a `MultiplexedPath`. Filter them out.

Fixes #311
---
 importlib_resources/readers.py          | 12 ++++++++----
 importlib_resources/tests/test_files.py |  3 ---
 newsfragments/311.bugfix.rst            |  1 +
 3 files changed, 9 insertions(+), 7 deletions(-)
 create mode 100644 newsfragments/311.bugfix.rst

diff --git a/importlib_resources/readers.py b/importlib_resources/readers.py
index dc649cf..4f761c6 100644
--- a/importlib_resources/readers.py
+++ b/importlib_resources/readers.py
@@ -138,19 +138,23 @@ class NamespaceReader(abc.TraversableResources):
     def __init__(self, namespace_path):
         if 'NamespacePath' not in str(namespace_path):
             raise ValueError('Invalid path')
-        self.path = MultiplexedPath(*map(self._resolve, namespace_path))
+        self.path = MultiplexedPath(*filter(bool, map(self._resolve, namespace_path)))
 
     @classmethod
-    def _resolve(cls, path_str) -> abc.Traversable:
+    def _resolve(cls, path_str) -> abc.Traversable | None:
         r"""
         Given an item from a namespace path, resolve it to a Traversable.
 
         path_str might be a directory on the filesystem or a path to a
         zipfile plus the path within the zipfile, e.g. ``/foo/bar`` or
         ``/foo/baz.zip/inner_dir`` or ``foo\baz.zip\inner_dir\sub``.
+
+        path_str might also be a sentinel used by editable packages to
+        trigger other behaviors (see python/importlib_resources#311).
+        In that case, return None.
         """
-        (dir,) = (cand for cand in cls._candidate_paths(path_str) if cand.is_dir())
-        return dir
+        dirs = (cand for cand in cls._candidate_paths(path_str) if cand.is_dir())
+        return next(dirs, None)
 
     @classmethod
     def _candidate_paths(cls, path_str: str) -> Iterator[abc.Traversable]:
diff --git a/importlib_resources/tests/test_files.py b/importlib_resources/tests/test_files.py
index 6fdcdef..f1fe233 100644
--- a/importlib_resources/tests/test_files.py
+++ b/importlib_resources/tests/test_files.py
@@ -8,8 +8,6 @@
 import importlib
 import contextlib
 
-import pytest
-
 import importlib_resources as resources
 from ..abc import Traversable
 from . import util
@@ -62,7 +60,6 @@ class OpenZipTests(FilesTests, util.ZipSetup, unittest.TestCase):
 class OpenNamespaceTests(FilesTests, util.DiskSetup, unittest.TestCase):
     MODULE = 'namespacedata01'
 
-    @pytest.mark.xfail(reason="#311")
     def test_non_paths_in_dunder_path(self):
         """
         Non-path items in a namespace package's ``__path__`` are ignored.
diff --git a/newsfragments/311.bugfix.rst b/newsfragments/311.bugfix.rst
new file mode 100644
index 0000000..56655f7
--- /dev/null
+++ b/newsfragments/311.bugfix.rst
@@ -0,0 +1 @@
+Omit sentinel values from a namespace path.
\ No newline at end of file