Don't crash if there exists an EGG-INFO directory on sys.path (#13667)

* Don't crash if there exists an EGG-INFO directory on sys.path

cross-port of https://gitlab.com/python-devs/importlib_metadata/merge_requests/72

* Also catch PermissionError for windows

Lib/importlib/metadata/__init__.py

@@ -320,7 +320,8 @@ class PathDistribution(Distribution):
         self._path = path
 
     def read_text(self, filename):
-        with suppress(FileNotFoundError, NotADirectoryError, KeyError):
+        with suppress(FileNotFoundError, IsADirectoryError, KeyError,
+                      NotADirectoryError, PermissionError):
             return self._path.joinpath(filename).read_text(encoding='utf-8')
     read_text.__doc__ = Distribution.read_text.__doc__
 

Lib/test/test_importlib/test_main.py

@@ -156,3 +156,11 @@ class DiscoveryTests(fixtures.EggInfoPkg,
             dist.metadata['Name'] == 'distinfo-pkg'
             for dist in dists
             )
+
+
+class DirectoryTest(fixtures.OnSysPath, fixtures.SiteDir, unittest.TestCase):
+    def test(self):
+        # make an `EGG-INFO` directory that's unrelated
+        self.site_dir.joinpath('EGG-INFO').mkdir()
+        # used to crash with `IsADirectoryError`
+        self.assertIsNone(version('unknown-package'))