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

4 files changed, 33 insertions, 14 deletions

diff --git a/Lib/doctest.py b/Lib/doctest.py
index baa503c..5bb35c9 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
 
diff --git a/Lib/inspect.py b/Lib/inspect.py
index ac127cb..7412d0e 100644
--- a/Lib/inspect.py
+++ b/Lib/inspect.py
@@ -707,10 +707,13 @@ def getsourcefile(object):
     if os.path.exists(filename):
         return filename
     # only return a non-existent filename if the module has a PEP 302 loader
-    if getattr(getmodule(object, filename), '__loader__', None) is not None:
+    module = getmodule(object, filename)
+    if getattr(module, '__loader__', None) is not None:
+        return filename
+    elif getattr(getattr(module, "__spec__", None), "loader", None) is not None:
         return filename
     # or it is in the linecache
-    if filename in linecache.cache:
+    elif filename in linecache.cache:
         return filename
 
 def getabsfile(object, _filename=None):
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:
diff --git a/Lib/site.py b/Lib/site.py
index 4d3b869..3a0f619 100644
--- a/Lib/site.py
+++ b/Lib/site.py
@@ -105,8 +105,15 @@ def makepath(*paths):
 def abs_paths():
     """Set all module __file__ and __cached__ attributes to an absolute path"""
     for m in set(sys.modules.values()):
-        if (getattr(getattr(m, '__loader__', None), '__module__', None) not in
-                ('_frozen_importlib', '_frozen_importlib_external')):
+        loader_module = None
+        try:
+            loader_module = m.__loader__.__module__
+        except AttributeError:
+            try:
+                loader_module = m.__spec__.loader.__module__
+            except AttributeError:
+                pass
+        if loader_module not in {'_frozen_importlib', '_frozen_importlib_external'}:
             continue   # don't mess with a PEP 302-supplied __file__
         try:
             m.__file__ = os.path.abspath(m.__file__)