2 files changed, 54 insertions, 2 deletions
diff --git a/Lib/importlib/resources/_common.py b/Lib/importlib/resources/_common.py
index e18082f..ca5b067 100644
--- a/Lib/importlib/resources/_common.py
+++ b/Lib/importlib/resources/_common.py
@@ -25,6 +25,8 @@ def package_to_anchor(func):
     >>> files('a', 'b')
     Traceback (most recent call last):
     TypeError: files() takes from 0 to 1 positional arguments but 2 were given
+
+    Remove this compatibility in Python 3.14.
     """
     undefined = object()
 
diff --git a/Lib/importlib/resources/readers.py b/Lib/importlib/resources/readers.py
index c3cdf76..b86cdef 100644
--- a/Lib/importlib/resources/readers.py
+++ b/Lib/importlib/resources/readers.py
@@ -1,7 +1,10 @@
 import collections
+import contextlib
 import itertools
 import pathlib
 import operator
+import re
+import warnings
 import zipfile
 
 from . import abc
@@ -62,7 +65,7 @@ class MultiplexedPath(abc.Traversable):
     """
 
     def __init__(self, *paths):
-        self._paths = list(map(pathlib.Path, remove_duplicates(paths)))
+        self._paths = list(map(_ensure_traversable, remove_duplicates(paths)))
         if not self._paths:
             message = 'MultiplexedPath must contain at least one path'
             raise FileNotFoundError(message)
@@ -130,7 +133,36 @@ class NamespaceReader(abc.TraversableResources):
     def __init__(self, namespace_path):
         if 'NamespacePath' not in str(namespace_path):
             raise ValueError('Invalid path')
-        self.path = MultiplexedPath(*list(namespace_path))
+        self.path = MultiplexedPath(*map(self._resolve, namespace_path))
+
+    @classmethod
+    def _resolve(cls, path_str) -> abc.Traversable:
+        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``.
+        """
+        (dir,) = (cand for cand in cls._candidate_paths(path_str) if cand.is_dir())
+        return dir
+
+    @classmethod
+    def _candidate_paths(cls, path_str):
+        yield pathlib.Path(path_str)
+        yield from cls._resolve_zip_path(path_str)
+
+    @staticmethod
+    def _resolve_zip_path(path_str):
+        for match in reversed(list(re.finditer(r'[\\/]', path_str))):
+            with contextlib.suppress(
+                FileNotFoundError,
+                IsADirectoryError,
+                NotADirectoryError,
+                PermissionError,
+            ):
+                inner = path_str[match.end() :].replace('\\', '/') + '/'
+                yield zipfile.Path(path_str[: match.start()], inner.lstrip('/'))
 
     def resource_path(self, resource):
         """
@@ -142,3 +174,21 @@ class NamespaceReader(abc.TraversableResources):
 
     def files(self):
         return self.path
+
+
+def _ensure_traversable(path):
+    """
+    Convert deprecated string arguments to traversables (pathlib.Path).
+
+    Remove with Python 3.15.
+    """
+    if not isinstance(path, str):
+        return path
+
+    warnings.warn(
+        "String arguments are deprecated. Pass a Traversable instead.",
+        DeprecationWarning,
+        stacklevel=3,
+    )
+
+    return pathlib.Path(path)