Only perform separator replacement if platform separator doesn't match tar separator

Author: 0xd6cb6d73

Lib/tarfile.py

@@ -2487,10 +2487,12 @@ def _get_extract_tarinfo(self, member, filter_function, path):
 
         if isinstance(member, str):
             unfiltered = self.getmember(member)
-            unfiltered = unfiltered.replace(r'/', os.sep)
+            if os.sep != r'/':
+                unfiltered = unfiltered.replace(r'/', os.sep)
         else:
             unfiltered = member
-            unfiltered.path = unfiltered.path.replace(r'/', os.sep)
+            if os.sep != r'/':
+                unfiltered.path = unfiltered.path.replace(r'/', os.sep)
 
         filtered = None
         try: