Unable to install signed, unlisted Webextension

I made a Webextension. I uploaded it as unlisted. The automated review was swift and it passed save for a warning advising against using jQuery 1.x

I see the .xpi in my list. When I click on it, the install process starts and the progress bar quickly reaches 100%, however it stays there forever, the “install” button remaining greyed out.

In Firefox, in the Add-Ons menu, I see that the extension is there, with a status of “Downloading”, and stays that way forever.

No other feedback appears whatsoever.

In the browser console I see

11:56:06.935 A promise chain failed to handle a rejection. Did you forget to '.catch', or did you forget to 'return'?
ee https://developer.mozilla.org/Mozilla/JavaScript_code_modules/Promise.jsm/Promise
Date: Mon Sep 26 2016 11:55:33 GMT+0200 (CEST)
Full Message: TypeError:  is not iterable
Full Stack: AddonInstall.prototype.onStopRequest/<@resource://gre/modules/addons/XPIProvider.jsm:5974:1
Handler.prototype.process@resource://gre/modules/Promise.jsm -> resource://gre/modules/Promise-backend.js:940:21
this.PromiseWalker.walkerLoop@resource://gre/modules/Promise.jsm -> resource://gre/modules/Promise-backend.js:816:7
this.PromiseWalker.scheduleWalkerLoop/<@resource://gre/modules/Promise.jsm -> resource://gre/modules/Promise-backend.js:750:11
XPIProvider.jsm:5974

I let everything brew for a couple of minutes, just in case : no change.

I can download the .xpi and tried to use the menu “install from file”. I can select the file, then nothing happens at all.

When I install the raw webextension in debug mode, everything is fine.

A couple of days ago I successfully used the same process to upload and install another a much simpler webextension and it went through like a breeze.

In spite, I deleted it and resubmited it as “listed” : currently awaiting full review.

So, in spite of AMO lending you a guiding hand throughout, is it still possible that I missed a step ? Could it be that the gentle warning is in fact a big no-no ?

Was the process recently broken ?

After an unlisted version is uploaded and signed, you should be able to download it and use it without any problems. It would have been interesting to give that file a look, but it sounds like you already deleted it and submitted it as listed, so we can’t know what went wrong.

I modified this extension to forgo jQuery altogether, which was on my roadmap anyway.
Same story as above, except this time without any warning at all.

I also tried the same procedure on a brand new profile, that I did not customize in any way. Same results.

This new version is here

https://addons.mozilla.org/en-US/developers/addon/skwares-firefox-no-jquery/edit

Edit : all of the above was on Ubuntu. I retried on Windows 10 and all went well at once.

More edit : I uninstalled the Firefox version from Canonical’s PPA, installed the 49.0.1 directly from Mozilla’s repo and everything is fine now, so it would appear there is a bug in Canonical’s version.

I’ve got the same problem for 2 of my extensions.
The problem seems to occurs on Firefox 49 packaged by Ubuntu, see https://bugs.launchpad.net/ubuntu/+source/firefox/+bug/1628014