Apply the same change to classes without an __getinitargs__() method

as in pickle: the new instance is created without calling __init__().

diff --git a/Lib/copy.py b/Lib/copy.py
index 51c375d65fcf53959547077c93e0ac8577e0d30a..1fbd48178af536cdfbd0f47ec2c07e962b0710bd 100644 (file)
--- a/Lib/copy.py
+++ b/Lib/copy.py
@@ -46,7 +46,7 @@ any similar types.
 
 Classes can use the same interfaces to control copying that they use
 to control pickling: they can define methods called __getinitargs__(),
-__getstate__() and __setstate__().  See the __doc__ string of module
+__getstate__() and __setstate__().  See the documentation for module
 "pickle" for information on these methods.
 """
 
@@ -107,9 +107,10 @@ def _copy_inst(x):
                return x.__copy__()
        if hasattr(x, '__getinitargs__'):
                args = x.__getinitargs__()
+               y = apply(x.__class__, args)
        else:
-               args = ()
-       y = apply(x.__class__, args)
+               y = _EmptyClass()
+               y.__class__ = x.__class__
        if hasattr(x, '__getstate__'):
                state = x.__getstate__()
        else:
@@ -219,9 +220,10 @@ def _deepcopy_inst(x, memo):
                args = x.__getinitargs__()
                _keep_alive(args, memo)
                args = deepcopy(args, memo)
+               y = apply(x.__class__, args)
        else:
-               args = ()
-       y = apply(x.__class__, args)
+               y = _EmptyClass()
+               y.__class__ = x.__class__
        memo[id(x)] = y
        if hasattr(x, '__getstate__'):
                state = x.__getstate__()
@@ -240,6 +242,10 @@ del d
 
 del types
 
+# Helper for instance creation without calling __init__
+class _EmptyClass:
+    pass
+
 def _test():
        l = [None, 1, 2L, 3.14, 'xyzzy', (1, 2L), [3.14, 'abc'],
             {'abc': 'ABC'}, (), [], {}]