60235 - Cannot override existing methods in new instances of sealed classes

Status: VERIFIED FIXED

(Rhino Graveyard :: Core, defect, P3)

Description

[David C. Navas]

I'm not sure if this is intended behavior or not -- it's odd if it's intended, 
as it makes it difficult to use sealed classes, but anyway....

If you create a sealed class, you cannot create an object whose prototype is 
that sealed class and override a method that was originally declared in the 
sealed class.

I changed this by doing the following, but I don't know what the definition of
sealed is.  I can see why it's a gray area, but if sealed objects are supposed 
to represent reusable prototypes, don't you need to override methods like 
toString(), etc?


Index: ScriptableObject.java
===================================================================
RCS file: /src/master/org/mozilla/javascript/ScriptableObject.java,v
retrieving revision 1.3
diff -u -r1.3 ScriptableObject.java
--- ScriptableObject.java       2000/11/04 00:10:09     1.3
+++ ScriptableObject.java       2000/11/15 21:44:29
@@ -226,7 +226,19 @@
         }
         Slot slot = slots[slotIndex];
         if ((slot.attributes & ScriptableObject.READONLY) != 0)
-            return;
+        {
+            // Allow function override, even if functions are sealed!
+            // Note that we can override a function to point to void or an actu
al property value,
+            // we should really check the existing value if we want to just sea
l functions.
+            // We don't want to make readonly properties settable, now, do we?!

+            // [Properties like Math.PI, etc...]
+//System.out.println("Setting: " + name + " to: " + value + " on: " + start + "
 for: " + this);
+            if ( start == this || !(slot.value instanceof Function)
+             ||  ((slot.flags & (Slot.HAS_SETTER|Slot.HAS_GETTER)) != 0) )
+            {
+                return;
+            }
+        }
         if ((slot.flags & Slot.HAS_SETTER) != 0) {
             GetterSlot getterSlot = (GetterSlot) slot;
             try {

Comment 1

[Igor Bukanov]

As a result of changes in sealed semantics, see bug 203013, one can now
overrides properties from object's prototype even if the prototype is sealed.

Comment 2

[Phil Schwartau]

Marking Verified - see bug 203013.

Comment 3

[Igor Bukanov]

Targeting as resolved against 1.5R5