Don't allow assignment to attributes named __*__

diff --git a/Objects/classobject.c b/Objects/classobject.c
index a4270e0adfebb985445c0aa6263f9468f5278120..ed0e6f4cc7a64e12f1388d4d6072fb6c0771fc92 100644 (file)
--- a/Objects/classobject.c
+++ b/Objects/classobject.c
@@ -1,5 +1,5 @@
 /***********************************************************
-Copyright 1991 by Stichting Mathematisch Centrum, Amsterdam, The
+Copyright 1991, 1992 by Stichting Mathematisch Centrum, Amsterdam, The
 Netherlands.
 
                         All Rights Reserved
@@ -106,7 +106,7 @@ class_getattr(op, name)
                int i;
                for (i = 0; i < n; i++) {
                        v = class_getattr((classobject *)
-                                         gettupleitem(op->cl_bases, i), name);
+                                       gettupleitem(op->cl_bases, i), name);
                        if (v != NULL)
                                return v;
                        err_clear();
@@ -122,6 +122,13 @@ class_setattr(op, name, v)
        char *name;
        object *v;
 {
+       if (name[0] == '_' && name[1] == '_') {
+               int n = strlen(name);
+               if (name[n-1] == '_' && name[n-2] == '_') {
+                       err_setstr(TypeError, "read-only special attribute");
+                       return -1;
+               }
+       }
        if (v == NULL)
                return dictremove(op->cl_methods, name);
        else
@@ -226,6 +233,13 @@ instance_setattr(inst, name, v)
        char *name;
        object *v;
 {
+       if (name[0] == '_' && name[1] == '_') {
+               int n = strlen(name);
+               if (name[n-1] == '_' && name[n-2] == '_') {
+                       err_setstr(TypeError, "read-only special attribute");
+                       return -1;
+               }
+       }
        if (v == NULL)
                return dictremove(inst->in_attr, name);
        else