# HG changeset patch
# User Paul Boddie <paul@boddie.org.uk>
# Date 1243036006 -7200
# Node ID 2fb8b284aba302f570328c8bf1195f5e17db49cd
# Parent  b58aae0af656187bf2c220b683e466577ea26382
Added callable context vs. self argument validation in CheckFrame, plus a test
which detects an attempt to fake the self argument with an incompatible
instance.

diff -r b58aae0af656 -r 2fb8b284aba3 rsvp.py
--- a/rsvp.py	Fri May 22 00:17:35 2009 +0200
+++ b/rsvp.py	Sat May 23 01:46:46 2009 +0200
@@ -508,17 +508,40 @@
             nlocals -= 1
         else:
             context_data = self.load(context_ref)
+
+            # Classes are not themselves usable as the self argument.
+            # NOTE: This may change at some point.
+            # However, where classes appear as the context, instance
+            # compatibility is required in the first argument.
+
             if context_data.attrcode is None: # absent attrcode == class
+
+                # Slide the frame to exclude the context.
+
                 self.local_sp_stack[-1] += 1
                 nlocals -= 1
 
-            # NOTE: Should check the context here.
+                # Check the context against the first argument.
+                # NOTE: Raise a proper exception here.
+
+                if nlocals > 0:
+                    self_context, self_ref = self.frame_stack[frame + 1]
+                    if not self._CheckInstance(self_ref, context_context):
+                        raise Exception, "CheckFrame %r (%r vs. %r)" % (self.operand, self.load(self_ref), self.load(context_context))
+                        #self.exception = self.type_error
+                        #return self.RaiseException()
+                else:
+                    raise Exception, "CheckFrame %r (no self argument)" % self.operand
+                    #self.exception = self.type_error
+                    #return self.RaiseException()
 
         # Test the frame size.
         # NOTE: Raise a proper exception here.
 
         if not ((nargs - ndefaults) <= nlocals and (nlocals <= nargs or has_star)):
             raise Exception, "CheckFrame %r (%r <= %r <= %r)" % (self.operand, nargs - ndefaults, nlocals, nargs)
+            #self.exception = self.type_error
+            #return self.RaiseException()
 
     def FillDefaults(self):
         # NOTE: Make the get_operand method of the instruction provide the
@@ -637,8 +660,11 @@
         # Find the table entry for the descendant.
 
         element = self.objlist[target_data.classcode + data.attrcode]
-        attr_index, class_attr, offset = element
-        return attr_index == data.attrcode
+        if element is not None:
+            attr_index, class_attr, offset = element
+            return attr_index == data.attrcode
+        else:
+            return 0
 
     def _MakeObject(self, size, ref):
         # Load the template.
diff -r b58aae0af656 -r 2fb8b284aba3 tests/attributes_class_bind_function_unbound_fake_self.py
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/tests/attributes_class_bind_function_unbound_fake_self.py	Sat May 23 01:46:46 2009 +0200
@@ -0,0 +1,16 @@
+#!/usr/bin/env python
+
+def e(self, x):
+    return x
+
+class C:
+    e = e
+
+class D:
+    e = C.e
+
+d = D()
+q = d.e # unbound C.e
+result = q(123, 321)
+
+# vim: tabstop=4 expandtab shiftwidth=4