The current plan is to have https://gerrit.wikimedia.org/r/#/c/207730/ fix this by using WANCache.

Note that the list is cached for 24 hours only, so updates will take about that long to propagate.

Any progress? I've just had confused Wikimedians ask me what kind of magic incantation they need to add a gadget, because just doing it no longer works. Can't we revert the bad change?

I would bump the priority, but it's already been "Unbreak now!" for a week. :(

Please, do something, roll-back 210260 or... disable completely the gadget extension. In the current state it is not possible to manage and supervise (introduced) changes in Gadgets extension. I have made a few changes (not knowing about the problems), ... waiting for the effects... and nothing happens - how do I test the changes if I do not know when they will appear in the users (and my) preferences tab?
Additional side effects of the problem (as I noticed) are such that changes in "Gadgets-definition" (i.e. new gadgets) occur in the users preferences tab for a moment (randomly) and the next time when I refresh the browser they disappear.
Testing the changes in gadgets-definition immediately as they are added is critical, and I can not imagine waiting "for 24 hours" every time when I change gadgets-definition.

Regards, Z.

The fix mentioned above was backported and deployed to WMF sites:
23:30 logmsgbot: ori Synchronized php-1.26wmf7/extensions/Gadgets: b592efa5fe: Update Gadgets for I6da3eede0: Conversion to using WAN cache (duration: 00m 13s)
Is it really still broken?

I have checked a while ago in plwikisource, and I receive randomly two various versions of the page (gadget list): sometimes the newest one, sometimes a few yesterday revisions older (a gadget was renamed yesterday).

@Krenair Yes, the problem still exists. I made a change in "MediaWiki:Gadgets-definition" a half-hour ago, and (on pl source) the changes are not visible. But, what we can observe is a state (of Special:Gadgets and Preferences) before the change, and randomly... state of "a few changes ago".
@Ankry: I made a change at 11:37 , so... the one of the version you can receive it's not "the newest one" but "before the change" :)

Currently, there is a third version that we can receive for a moment (randomly) - version before all the changes of the last two days (without new Gadgets), but... not the newest one :(

Regards, Z.

@ori: Any input here, regarding the last comment? Thanks in advance.

Is this fixed now? It's been "Unbreak Now!" for two weeks now. @ori, are you working on this? The lac of updates here is disappointing :(

I confirm, gadget definition page updates are visible immediately, no delay (1.26wmf8 (rMWdab1803da438) on plwikisource).