- Insert an image from Commons
- Press Ctrl+Z quickly
When you undo the image insertion, there's still an API request pending. When it comes back, ve.ce.GeneratedContentNode.prototype.doneGenerating crashes because the node is now detached.
GCNode should protect against being detached, and should abort any pending requests when it's detached (the latter alone is not enough: GCNode promises aren't guaranteed to be abortable).