bpo-44070: No longer eagerly makes import filenames absolute, except for extension modules (GH-26025)

Lib/importlib/_bootstrap_external.py

@@ -718,11 +718,6 @@ def spec_from_file_location(name, location=None, *, loader=None,
                 pass
     else:
         location = _os.fspath(location)
-        if not _path_isabs(location):
-            try:
-                location = _path_join(_os.getcwd(), location)
-            except OSError:
-                pass
 
     # If the location is on the filesystem, but doesn't actually exist,
     # we could return None here, indicating that the location is not
@@ -1159,6 +1154,11 @@ class ExtensionFileLoader(FileLoader, _LoaderBasics):
 
     def __init__(self, name, path):
         self.name = name
+        if not _path_isabs(path):
+            try:
+                path = _path_join(_os.getcwd(), path)
+            except OSError:
+                pass
         self.path = path
 
     def __eq__(self, other):

Lib/test/test_importlib/test_spec.py

@@ -815,10 +815,10 @@ class FactoryTests:
 
         self.assertEqual(spec.name, self.name)
         self.assertEqual(spec.loader, self.fileloader)
-        self.assertEqual(spec.origin, self.path)
+        self.assertEqual(spec.origin, os.path.basename(self.path))
         self.assertIs(spec.loader_state, None)
         self.assertIs(spec.submodule_search_locations, None)
-        self.assertEqual(spec.cached, self.cached)
+        self.assertEqual(spec.cached, os.path.relpath(self.cached))
         self.assertTrue(spec.has_location)
 
 (Frozen_FactoryTests,

Misc/NEWS.d/next/Core and Builtins/2021-05-10-22-30-12.bpo-44070.5bBtKx.rst

@@ -0,0 +1,2 @@
+No longer eagerly makes import filenames absolute, except for extension
+modules.