Overridden methods now property return instance when returning 'this'

- There may be a cleaner way to do this. This is a quick fix.

lib/member_builder.js

@@ -319,12 +319,22 @@ function overrideMethod( super_method, new_method, instCallback )
     {
         override = function()
         {
+            var context = instCallback( this ) || this,
+                retval  = undefined
+            ;
+
             // the _super property will contain the parent method
             this.__super = super_method;
 
-            var retval = new_method.apply(
-                ( instCallback( this ) || this ), arguments
-            );
+            retval = new_method.apply( context, arguments );
+
+            // if the value returned from the method was the context that we
+            // passed in, return the actual instance (to ensure we do not break
+            // encapsulation)
+            if ( retval === context )
+            {
+                return this;
+            }
 
             return retval;
         };

test/test-class-visibility.js

@@ -67,13 +67,25 @@ var common  = require( './common' ),
         {
             return this;
         },
+
+
+        'public getSelfOverride': function()
+        {
+            // override me
+        },
     }),
 
     // instance of Foo
     foo = Foo(),
 
     // subtype
-    SubFoo  = Foo.extend( {} ),
+    SubFoo  = Foo.extend({
+        'public getSelfOverride': function()
+        {
+            // return this from overridden method
+            return this;
+        },
+    }),
     sub_foo = SubFoo()
 ;
 
@@ -341,5 +353,12 @@ var common  = require( './common' ),
         sub_foo,
         "Returning 'this' from a super method should return the subtype"
     );
+
+    // finally, overridden methods should still return the instance
+    assert.deepEqual(
+        sub_foo.getSelfOverride(),
+        sub_foo,
+        "Returning 'this' from a overridden method should return the subtype"
+    );
 } )();