Warn when reordering nodes that have been moved outside of React

[sophiebits]

For the MOVE_EXISTING update type, it would be nice if DOMChildrenOperations checked data-reactid and warned if the child it finds isn't the expected node.

[syranide]

If we go with #1570 there will be no data-reactid to check for. However, if we remove my PR's dependency on _mountIndex it will "by necessity" validate that all the nodes are of the right type and that there aren't too few/many for that parent. I guess it could also check that the parentNode is indeed the correct parent node (i.e, if the node is the expected one).

[sophiebits]

Well, perhaps we could still check against React's node cache. I've seen a few people get confused when trying to integrate React with an external sortable plugin because the plugin moves the nodes around and then React can't find the right ones.

[syranide]

@spicyj Yeah definitely, but what I mentioned above is really all that we can do (given #1570). If a node isn't in the cache, we evaluate as usual and if the expected children node types doesn't match (including count and order) it's an error by default. If the node was in the cache (it has been tagged), we can check the parent and make sure it's the correct one. There's nothing else we can do (I think?) since elements would not be "pre-tagged" as they are today.

[gaearon]

Closing as stale. If there is enough interest please reopen or file a new issue.