I don't know why staring at the email to python-checkins made me

see problems with my code that I didn't see before the checkin, but:

When a subtype .mro() fails, we need to reset the type whose __bases__
are being changed, too.  Fix + test.

diff --git a/Lib/test/test_descr.py b/Lib/test/test_descr.py
index 19a0ae49241388c2d774cd868d2c30b929ecd18f..99eecd3f9e015ea84a567bebfa51d7ee0d22cebc 100644 (file)
--- a/Lib/test/test_descr.py
+++ b/Lib/test/test_descr.py
@@ -3566,11 +3566,13 @@ def test_mutable_bases_with_failing_mro():
     # check here that E's gets restored.
     
     E_mro_before = E.__mro__
+    D_mro_before = D.__mro__
 
     try:
         D.__bases__ = (C2,)
     except RuntimeError:
         vereq(E.__mro__, E_mro_before)
+        vereq(D.__mro__, D_mro_before)
     else:
         raise TestFailed, "exception not propagated"
 

diff --git a/Objects/typeobject.c b/Objects/typeobject.c
index 949cef58eeeb2a3b2e36c5015134725966e78da2..d83ff8cab58ba8a2776a3a28870806f25434f103 100644 (file)
--- a/Objects/typeobject.c
+++ b/Objects/typeobject.c
@@ -242,17 +242,12 @@ type_set_bases(PyTypeObject *type, PyObject *value, void *context)
        type->tp_base = new_base;
 
        if (mro_internal(type) < 0) {
-               type->tp_bases = old_bases;
-               type->tp_base = old_base;
-               type->tp_mro = old_mro;
-
-               Py_DECREF(value);
-               Py_DECREF(new_base);
-
-               return -1;
+               goto bail;
        }
 
        temp = PyList_New(0);
+       if (!temp)
+               goto bail;
 
        r = mro_subclasses(type, temp);
 
@@ -267,7 +262,7 @@ type_set_bases(PyTypeObject *type, PyObject *value, void *context)
                        Py_INCREF(cls->tp_mro);
                }
                Py_DECREF(temp);
-               return r;
+               goto bail;
        }
 
        Py_DECREF(temp);
@@ -303,6 +298,16 @@ type_set_bases(PyTypeObject *type, PyObject *value, void *context)
        Py_DECREF(old_mro);
 
        return r;
+
+  bail:
+       type->tp_bases = old_bases;
+       type->tp_base = old_base;
+       type->tp_mro = old_mro;
+       
+       Py_DECREF(value);
+       Py_DECREF(new_base);
+       
+       return -1;
 }
 
 static PyObject *