1444468 - [meta] Remove use of XUL overlays in Thunderbird

Status: RESOLVED FIXED

(Thunderbird :: General, enhancement)

Description

[Boris Zbarsky [:bzbarsky]]

See bug 1426763.

Firefox is getting rid of use of XUL overlays.  Once that happens we will likely remove overlay support from Gecko.

The dependency tree of bug 1426763 has examples of how Firefox is moving away from overlays.  At first glance they are mostly getting inlined or replaced with preprocessing.

I am given to understand that ETA here is order of "a week" for Firefox to stop using overlays and that we'd then work on the Gecko removal.

Comment 1

[Jorg K (CEST = GMT+2)]

Richard, thanks for starting to tackle this. How many overlays do we need to remove?

Comment 2

[Richard Marti (:Paenglab)]

There are many. Sometimes also overlays of overlays, like bug 1444596. A problem I'm seeing is that we also have overlays in mailnews touching SM too.

First I fix the low hanging fruits.

Comment 3

[:aceman]

So faking overlays via preprocessing and including files. So it does not much remove the concept of sharing some XUL, just makes development slower and kills addons (as they can't do preprocessing). The progress...

Comment 4

[Boris Zbarsky [:bzbarsky]]

Is Thunderbird still supporting non-webextension addons?  I suspect the platform support around those is going to get worse and worse; in particular Gecko changes are being made with the assumption that non-webextension addons do not exist.

(And yes, it's progress in terms of reducing technical debt in Gecko...)

On the question of how many overlays, SeaMonkey has a ton, but Thunderbird has a lot fewer, fwiw.

Comment 5

[Jorg K (CEST = GMT+2)]

(In reply to Boris Zbarsky [:bz] (no decent commit message means r-) from comment #4)
> Is Thunderbird still supporting non-webextension addons?
Yes, you can find news regarding this subject here: https://wiki.mozilla.org/Thunderbird/Add-ons_Guide_57

There are many add-ons in the Thunderbird ecosystem and we try to support all legacy add-ons, both non-bootstrapped ones and bootstrapped ones. Our current support for WebExtension add-ons is rather poor, see bug 1396172. Certainly we don't have any interfaces defined yet where WebExtensions could manipulate "mail things". Or maybe I'm misunderstanding how WebExtensions work in the first place.

> I suspect the
> platform support around those is going to get worse and worse; in particular
> Gecko changes are being made with the assumption that non-webextension
> addons do not exist.
I was under the impression that support for non-bootstrapped add-ons is being removed, but that FF still supports "system add-ons" (sorry, I only heard the term without exactly knowing what they are) and some enterprise add-ons. Hence the "policy manager" changes which delayed ESR 59 to ESR 60. Or maybe I got it all wrong.

> On the question of how many overlays, SeaMonkey has a ton, but Thunderbird
> has a lot fewer, fwiw.
Right, I did a bit of counting and removing overlays in TB seems doable, in fact we already removed four, there a patches for two more and I'd estimate that the removal can be done in a matter of weeks. Besides, I still count five left to do in FF looking at bug 1426763.

Comment 6

[Boris Zbarsky [:bzbarsky]]

We're getting way off topic here, but....

> but that FF still supports "system add-ons" 

Firefox supports them.  However any given API is subject to removal if it's not used by Firefox itself.  There are also other changes, like renaming functions and whatnot, that are basically assuming that we don't have to worry about compat with any addons.  System add-ons are expected to get updated or otherwise deal.

There are also security changes being made with arguments like "this is only a problem if this pref is set, and we know addons can't set prefs".  Which is true for webextensions, and we sort of trust "system add-ons" to not mess up...

> Besides, I still count five left to do in FF looking at bug 1426763.

Right.  ETA I was told for FF killing off overlays completely is ~1 week.

Comment 7

[Jorg K (CEST = GMT+2)]

Attachment: report-overlay-load.patch

Patch to report loaded overlays.

Comment 8

[Brendan Dahl [:bdahl]]

Do you have a rough ETA for the removal of the remaining overlays?

Comment 9

[Jorg K (CEST = GMT+2)]

Very good question. Since we mostly operate in fire-fighting mode and there are always hotter fires burning, the last three overlays, add-ons page for styling, some about:config page to handle ESC and the dev tools, have slipped back in priority. The first two could be just removed, devtools are harder.

Let me return the question: What are your plans? I'd say we could possibly get something going within two weeks.

Richard, can you just do the removal in bug 1450467? Or would M-C be prepared to implement that? Aceman any cycles for bug 1450218? Maybe that give us some insight into how to handle bug 1450465.

Comment 10

[Richard Marti (:Paenglab)]

Yes, I'll do it. I doubt they will add it because FX loads it in a tab as a normal page.

Comment 11

[Jorg K (CEST = GMT+2)]

(In reply to Brendan Dahl [:bdahl] from comment #8)
> Do you have a rough ETA for the removal of the remaining overlays?
OK, two will go in the next 24 hours, working patches with r? or r+. Perhaps give the very last one another week.

Comment 12

[Brendan Dahl [:bdahl]]

(In reply to Jorg K (GMT+1) from comment #9)
> Let me return the question: What are your plans? I'd say we could possibly
> get something going within two weeks.

My hope is to have it removed this quarter, ideally before the end of May. I'm fine with waiting, if you all are thinking it will be within the next few weeks. Also, I've got some patches almost ready for the removal, but I'm guessing the review is going to take awhile.

Comment 13

[Jorg K (CEST = GMT+2)]

Brendan, there is one overlay left, Aceman is onto it, so please don't wait for us any more. And of course, BIG THANKS for coordinating the effort!

Comment 14

[Jorg K (CEST = GMT+2)]

We've removed all XUL overlays in Thunderbird. We're working on getting rid of the remaining "CSS overlays", see bug 1450757.

Implementing an overlay loader or similar for Calendar and other add-ons, bug 1448808, should not block this bug.