SF patch 560794 (Greg Chapman): deepcopy can't handle custom

metaclasses.

This is essentially the same problem as that reported in bug 494904
for pickle: deepcopy should treat instances of custom metaclasses the
same way it treats instances of type 'type'.

Bugfix candidate.

Lib/copy.py

@@ -163,6 +163,13 @@ def deepcopy(x, memo = None):
     try:
         copierfunction = _deepcopy_dispatch[type(x)]
     except KeyError:
+        try:
+            issc = issubclass(type(x), type)
+        except TypeError:
+            issc = 0
+        if issc:
+            y = _deepcopy_dispatch[type](x, memo)
+        else:
             try:
                 copier = x.__deepcopy__
             except AttributeError: