_common: make as_file return the real file on os.PathLike

We currently have custom handling for pathlib.Path, but that means
that custom readers that do not using pathlib.Path will have their
traversables copied to a temporary directory in as_file, which can be an
expensive operation.
By adding a dispatch for os.PathLike, we extend this behavior for all
path-like objects.

Signed-off-by: Filipe Laíns <lains@riseup.net>

Author: FFY00

importlib_resources/_common.py

@@ -109,8 +109,17 @@ def as_file(path):
 
 @as_file.register(pathlib.Path)
 @contextlib.contextmanager
-def _(path):
+def _as_file_pathlib(path):
     """
     Degenerate behavior for pathlib.Path objects.
     """
     yield path
+
+
+@as_file.register(os.PathLike)
+@contextlib.contextmanager
+def _as_file_pathlike(path):
+    """
+    Degenerate behavior for os.PathLike objects.
+    """
+    yield pathlib.Path(os.fspath(path))

importlib_resources/tests/test_path.py

@@ -1,7 +1,10 @@
 import io
+import os
+import pathlib
 import unittest
 
 import importlib_resources as resources
+from importlib_resources.abc import TraversableResources
 from . import data01
 from . import util
 
@@ -57,5 +60,39 @@ def test_remove_in_context_manager(self):
             path.unlink()
 
 
+class PathLikeTests(PathTests, unittest.TestCase):
+    class PathLikeTraversable:
+        """pathlib.Path proxy, is os.PathLike but is not pathlib.Path"""
+
+        def __init__(self, *args, **kwargs):
+            self._path = pathlib.Path(*args, **kwargs)
+
+        def __fspath__(self):
+            return os.fspath(self._path)
+
+        def joinpath(self, other):
+            return self.__class__(self, other)
+
+        __truediv__ = joinpath
+
+        @property
+        def parent(self):
+            return self.__class__(self._path.parent)
+
+    class PathLikeResources(TraversableResources):
+        def __init__(self, loader):
+            self.path = PathLikeTests.PathLikeTraversable(loader.path).parent
+
+        def get_resource_reader(self, package):
+            return self
+
+        def files(self):
+            return self.path
+
+    def setUp(self):
+        reader = self.PathLikeResources(data01.__loader__)
+        self.data = util.create_package_from_loader(reader)
+
+
 if __name__ == '__main__':
     unittest.main()