[TIMOB-8065] Implemented checks against laying out destroyed children.

[nebrius]

No description provided.

[cb1kenobi]

I'm not 100% sure why we need this, but we'll leave it in just in case. I wonder if we should put it before the for loop, so that it certainly would overwrite whatever _alive value was there prevously, then it would get deleted by the for loop. We can revisit later.

[cb1kenobi]

After doing some tests, this solution seems to fix the issue where a View is marked for layout, but then is deleted before the setTimeout fires to do the actual layout.

This method does the check in the layout and requires 1 function call to verifyChild() which has 2 conditional checks per node to layout. Generally, all nodes will be valid.

It might be better for Views to explicitly remove themselves from the nodesToLayout array. Instead of markedForLayout being true/false, it could be -1 if not marked for layout or 0+ for the index in the nodesToLayout array. When a view is remove()'d, it would do a quick !~markedForLayout and if true, set nodesToLayout[markedForLayout] = null.

What is less code? What is more performant?

[nebrius]

I tried removing the nodes from the marked for layout list, but unfortunately that doesn't help. The problem is that these nodes that are not alive but not removed are not in the marked for layout list, but instead are dependent on a node in the list. The dependencies are not calculated until later, after the node has already been destroyed, so the node has no way of knowing if it will be laid out when it is destroyed.

[cb1kenobi]

OK, then that makes good sense.

Code reviewed and tested. Request accepted.