bpo-42133: update parts of the stdlib to fall back to `__spec__.loader` when `__loader__` is missing (#22929)

1 files changed, 11 insertions, 7 deletions

diff --git a/Lib/doctest.py b/Lib/doctest.py
index baa503c83f..5bb35c9715 100644
--- a/Lib/doctest.py
+++ b/Lib/doctest.py
@@ -222,13 +222,17 @@ def _load_testfile(filename, package, module_relative, encoding):
     if module_relative:
         package = _normalize_module(package, 3)
         filename = _module_relative_path(package, filename)
-        if getattr(package, '__loader__', None) is not None:
-            if hasattr(package.__loader__, 'get_data'):
-                file_contents = package.__loader__.get_data(filename)
-                file_contents = file_contents.decode(encoding)
-                # get_data() opens files as 'rb', so one must do the equivalent
-                # conversion as universal newlines would do.
-                return _newline_convert(file_contents), filename
+        if (loader := getattr(package, '__loader__', None)) is None:
+            try:
+                loader = package.__spec__.loader
+            except AttributeError:
+                pass
+        if hasattr(loader, 'get_data'):
+            file_contents = loader.get_data(filename)
+            file_contents = file_contents.decode(encoding)
+            # get_data() opens files as 'rb', so one must do the equivalent
+            # conversion as universal newlines would do.
+            return _newline_convert(file_contents), filename
     with open(filename, encoding=encoding) as f:
         return f.read(), filename