Closes #18940: Merged fix from 3.3.

Lib/logging/handlers.py

@@ -109,6 +109,8 @@ class BaseRotatingHandler(logging.FileHandler):
                        what the source is rotated to, e.g. 'test.log.1'.
         """
         if not callable(self.rotator):
+            # Issue 18940: A file may not have been created if delay is True.
+            if os.path.exists(source):
                 os.rename(source, dest)
         else:
             self.rotator(source, dest)