move atomic check before memo check

eendebakpt · eendebakpt · commit b8c57fafa878 · 2024-01-19T20:47:33.000+01:00
diff --git a/Lib/copy.py b/Lib/copy.py
@@ -121,6 +121,13 @@ def deepcopy(x, memo=None, _nil=[]):
     See the module's __doc__ string for more info.
     """
 
+    cls = type(x)
+    copier = _deepcopy_dispatch.get(cls)
+
+    if copier is ...:
+        # atomic type
+        return x
+
     d = id(x)
     if memo is None:
         memo = {}
@@ -129,13 +136,6 @@ def deepcopy(x, memo=None, _nil=[]):
         if y is not _nil:
             return y
 
-    cls = type(x)
-
-    copier = _deepcopy_dispatch.get(cls)
-    
-    if copier is ...:
-        # atomic type
-        return x
     
     if copier is not None:
         y = copier(x, memo)
