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

1 files changed, 8 insertions, 3 deletions

diff --git a/Lib/linecache.py b/Lib/linecache.py
index fa5dbd0..513b17e 100644
--- a/Lib/linecache.py
+++ b/Lib/linecache.py
@@ -165,9 +165,14 @@ def lazycache(filename, module_globals):
     if not filename or (filename.startswith('<') and filename.endswith('>')):
         return False
     # Try for a __loader__, if available
-    if module_globals and '__loader__' in module_globals:
-        name = module_globals.get('__name__')
-        loader = module_globals['__loader__']
+    if module_globals and '__name__' in module_globals:
+        name = module_globals['__name__']
+        if (loader := module_globals.get('__loader__')) is None:
+            if spec := module_globals.get('__spec__'):
+                try:
+                    loader = spec.loader
+                except AttributeError:
+                    pass
         get_source = getattr(loader, 'get_source', None)
 
         if name and get_source: