SF patch #685738 by Michael Stone.

This changes the default __new__ to refuse arguments iff tp_init is the
default __init__ implementation -- thus making it a TypeError when you
try to pass arguments to a constructor if the class doesn't override at
least __init__ or __new__.

2 files changed, 14 insertions, 11 deletions

diff --git a/Lib/copy_reg.py b/Lib/copy_reg.py
index 11ae960..6dc52c2 100644
--- a/Lib/copy_reg.py
+++ b/Lib/copy_reg.py
@@ -33,11 +33,14 @@ def pickle_complex(c):
 
 pickle(type(1j), pickle_complex, complex)
 
-# Support for picking new-style objects
+# Support for pickling new-style objects
 
 def _reconstructor(cls, base, state):
-    obj = base.__new__(cls, state)
-    base.__init__(obj, state)
+    if base is object:
+        obj = object.__new__(cls)
+    else:
+        obj = base.__new__(cls, state)
+        base.__init__(obj, state)
     return obj
 
 _HEAPTYPE = 1<<9
diff --git a/Lib/test/test_descr.py b/Lib/test/test_descr.py
index 77bf61a..ffd86bc 100644
--- a/Lib/test/test_descr.py
+++ b/Lib/test/test_descr.py
@@ -3694,8 +3694,8 @@ def subclass_right_op():
         def __rdiv__(self, other):
             return "C.__rdiv__"
 
-    vereq(C(1) / 1, "C.__div__")
-    vereq(1 / C(1), "C.__rdiv__")
+    vereq(C() / 1, "C.__div__")
+    vereq(1 / C(), "C.__rdiv__")
 
     # Case 3: subclass of new-style class; here it gets interesting
 
@@ -3705,8 +3705,8 @@ def subclass_right_op():
         def __rdiv__(self, other):
             return "D.__rdiv__"
 
-    vereq(D(1) / C(1), "D.__div__")
-    vereq(C(1) / D(1), "D.__rdiv__")
+    vereq(D() / C(), "D.__div__")
+    vereq(C() / D(), "D.__rdiv__")
 
     # Case 4: this didn't work right in 2.2.2 and 2.3a1
 
@@ -3715,10 +3715,10 @@ def subclass_right_op():
 
     vereq(E.__rdiv__, C.__rdiv__)
 
-    vereq(E(1) / 1, "C.__div__")
-    vereq(1 / E(1), "C.__rdiv__")
-    vereq(E(1) / C(1), "C.__div__")
-    vereq(C(1) / E(1), "C.__div__") # This one would fail
+    vereq(E() / 1, "C.__div__")
+    vereq(1 / E(), "C.__rdiv__")
+    vereq(E() / C(), "C.__div__")
+    vereq(C() / E(), "C.__div__") # This one would fail
 
 def dict_type_with_metaclass():
     if verbose: