gh-85702: Catch IsADirectoryError in zoneinfo (#131333)

Co-authored-by: Victor Stinner <[email protected]>

Author: StanFromIreland

Diff for: Lib/test/test_zoneinfo/test_zoneinfo.py

@@ -222,6 +222,7 @@ def test_bad_keys(self):
             "America.Los_Angeles",
             "🇨🇦",  # Non-ascii
             "America/New\ud800York",  # Contains surrogate character
+            "Europe",  # Is a directory, see issue gh-85702
         ]
 
         for bad_key in bad_keys:

Diff for: Lib/zoneinfo/_common.py

@@ -10,7 +10,7 @@ def load_tzdata(key):
 
     try:
         return resources.files(package_name).joinpath(resource_name).open("rb")
-    except (ImportError, FileNotFoundError, UnicodeEncodeError):
+    except (ImportError, FileNotFoundError, UnicodeEncodeError, IsADirectoryError):
         # There are three types of exception that can be raised that all amount
         # to "we cannot find this key":
         #
@@ -21,6 +21,7 @@ def load_tzdata(key):
         #   (e.g. Europe/Krasnoy)
         # UnicodeEncodeError: If package_name or resource_name are not UTF-8,
         #   such as keys containing a surrogate character.
+        # IsADirectoryError: If package_name without a resource_name specified.
         raise ZoneInfoNotFoundError(f"No time zone found with key {key}")
 
 

Diff for: Misc/NEWS.d/next/Library/2025-03-16-17-40-00.gh-issue-85702.qudq12.rst

@@ -0,0 +1,2 @@
+If ``zoneinfo._common.load_tzdata`` is given a package without a resource a
+``ZoneInfoNotFoundError`` is raised rather than a :exc:`IsADirectoryError`.