In both these cases, one JavaScript cannot stop, the browser freezes and after some time Firefox displays a popup about a not responding JavaScript. When not clicking on "Stop", the saving animation (for case 2) continuous to run indefinitely.
tested with Firefox 55 and 57, German wiki. (tested with: https://de.wikipedia.org/wiki/Threema)
| Subject | Repo | Branch | Lines +/- | |
|---|---|---|---|---|
| Debounce reference list updates | mediawiki/extensions/Cite | master | +6 -4 |
This seems to be a performance problem somehow related to large articles on the German Wikipedia. I tried to reproduce with some large articles, and some random articles; all the large articles had this problem, and all the random articles (which tend to be smaller) did not.
I also tested in some large articles on the English Wikipedia, and could not reproduce this problem, although the reference box did seem a little bit slower than it should, so it seems like this is a more general performance problem that is affecting the German Wikipedia in a particularly disastrous fashion.
Large articles:
Random articles:
The problem is they have started using the <references> tag again, which is a good thing because it means the ref list updates dynamically. Unfortunately the large wikis have been using {{references}} templates for so long that we haven't noticed the performance issues.
Change 378690 had a related patch set uploaded (by Esanders; owner: Esanders):
[mediawiki/extensions/Cite@master] Debounce reference list updates
The above patch fixes the symptom if not the cause.
Pseudo-tested on de.wiki by pasting the following monkey patch in the console:
ve.ce.MWReferencesListNode.prototype._update = ve.ce.MWReferencesListNode.prototype.update; ve.ce.MWReferencesListNode.prototype.update = ve.debounce( ve.ce.MWReferencesListNode.prototype._update );
Change 378690 merged by jenkins-bot:
[mediawiki/extensions/Cite@master] Debounce reference list updates
I think TreeModifier could be to blame, emitting more events than we used to and causing the list to rebuild many more times. Pinging @dchan .
Patch for this open Unbreak now! priority task has been merged two weeks ago.
What is left to do here?
There's no patch to review here any more, but as I noted above, there's still other work to be done.
What remains here is essentially the same as T134975, so I'm going to merge them together.