Infinite digest loop when using filters inside tooltip expression properties (like popover-html)

[forceuser]

There is an error when using filters inside expression (as example popover-html="'some html' | to_trusted") it caused infinite digest loop (Error message: [$rootScope:infdig] 10 $digest() iterations reached. Aborting!).
The reason is:
scope updates > triggers tooltipLinkedScope 'contentExp()' watcher > scope.$eval(attrs[type]) can again trigger update of the scope

I changed contentExp to evaluate using $parse instead of scope.$eval and moved it to scope watcher

Now contentExp() returns already evaluated value and can't cause infinite loop

[wesleycho]

@RobJacobs what are your thoughts on this? This sounds like a good change IMO, since evaluating the attribute expression each time is inefficient.

[RobJacobs]

@wesleycho @forceuser I like where this is going but have a suggestion. Lets see if we can move the watch to the createTooltip function and replace the watch on line 229 for contentExp(), so that it would become:

if (options.useContentExp) {
  tooltipLinkedScope.$watch(contentExpGetter, function(val) {
    contentExpVal = val;
    if (!val && ttScope.isOpen) {
      hide();
     }
    });
....
}

That way, when the tooltipLinkedScope gets destroyed, so does the watch and that watch can serve both purposes (hide tooltip when template is empty).

[forceuser]

but the parent of tooltipLinkedScope is ttScope and it is isolated, so contentExpGetter may not return any value in tooltipLinkedScope.$watch