[Laszlo-dev] Looking at 'No eventSender' error

[Philip Romanik]

Hi Tucker,

I'm looking into LPP-3141 to see why the 'No eventSender' message is 
generated. I think I should fix LzNode.applyConstraint() to not call 
LzDelegate.register() when the object is null. I'm looking at a case from 
basecomponent.lzx:

<attribute name="_enabled"
   value="${this.enabled &amp;&amp; (this._parentcomponent ?
     this._parentcomponent._enabled : true)}"
   setter="this._setEnabled(_enabled)"/>

As I understand constraints, the dependency [this._parentcomponent, 
'_enabled'] will generate on_enabled events. This will happen even if 
this._parentcomponent is null.
If this._parentcomponent is null, the error message gets printed by 
LzDelegate.register(). But if I fix LzNode.applyConstraint(),

function applyConstraint ( prop , cfunc, dep ){
...
     if ( dep.length ){
         var l = dep.length;
         for ( var i = 0 ; i < l ; i+=2 ){
             if (dep[ i ]) {   // ***NEW LINE
                 var d = new LzDelegate( this , refF );
                 this.__LZdelegates.push( d );
                 d.register( dep[ i ] , "on" + dep[ i + 1 ] );
             }  // ***NEW LINE
         }
     }
...
}

everything works. Removing the error message in LzDelegate.register() seems 
wrong to me. What do you think?

Phil