818400 - Unprefix :-moz-scope and pref it off by default on beta and release channel

Status: RESOLVED FIXED

(Core :: CSS Parsing and Computation, defect)

Description

[Masatoshi Kimura [:emk]]

Please do not proliferate prefixes anymore.

Comment 1

[Boris Zbarsky [:bzbarsky]]

Hmm.  So the idea would be to not parse :scope, right?

Comment 2

[Masatoshi Kimura [:emk]]

I bore @supports in mind.

Comment 3

[Boris Zbarsky [:bzbarsky]]

Sure.

I'll see what I can cook up, I guess.

Comment 4

[Boris Zbarsky [:bzbarsky]]

Attachment: Add a preference to control :scope and pref it off.

Just preffed off for now until we have a setup for auto-preffing-off on beta/release, I guess

Comment 5

[David Baron :dbaron: (⌚️UTC-4, no longer working on Mozilla)]

I guess ifdefs in all.js based on MOZ_UPDATE_CHANNEL would work for the actual builds, but would confuse everybody doing their own build (since that has MOZ_UPDATE_CHANNEL set to default)?

Comment 6

[Boris Zbarsky [:bzbarsky]]

Yeah...  We really need a better solution for this stuff.

Also, I think we should actually use the same pref as <style scoped> for :scope.  I'm just not sure what that is.

Comment 7

[Cameron McCormack (:heycam)]

My patches for <style scoped> don't actually use a pref at the moment (I misremembered that they did).

Comment 8

[Boris Zbarsky [:bzbarsky]]

Note that I'm also fine with shipping :scope unprefixed and unpreffed.  Not sure how happy everyone else is with that, though.

Comment 9

[David Baron :dbaron: (⌚️UTC-4, no longer working on Mozilla)]

Comment on attachment 690052 [details] [diff] [review]
Add a preference to control :scope and pref it off.

Why don't you leave it on for nightly/aurora using the mechanism added in bug 820148 (though see bug 814530 -- I'm not completely confident it works yet)?

r=dbaron

Comment 10

[David Baron :dbaron: (⌚️UTC-4, no longer working on Mozilla)]

er, meant to say "though see bug 814530 comment 6"

Comment 11

[Boris Zbarsky [:bzbarsky]]

> Why don't you leave it on for nightly/aurora using the mechanism added in bug 820148 

That's the plan once that mechanism works; this patch predates that mechanism existing...

Comment 12

[Boris Zbarsky [:bzbarsky]]

https://hg.mozilla.org/integration/mozilla-inbound/rev/066cdafa5ec3 using the new ifdef magic.

Comment 13

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/mozilla-central/rev/066cdafa5ec3

Comment 14

[Dão Gottwald [:dao]]

Is there a bug for preffing this on? What are the conditions for this to happen? RELEASE_BUILD has the side effect of making it opaque if and when we can start using new CSS features in our code base.

Comment 15

[Boris Zbarsky [:bzbarsky]]

> Is there a bug for preffing this on?

Not yet.

> What are the conditions for this to happen? 

Not clear yet.  :(

Comment 16

[Boris Zbarsky [:bzbarsky]]

That said, I think we should enable this and scoped stylesheets together, so the conditions should be the same.

Comment 17

[Cameron McCormack (:heycam)]

I didn't put the scoped stylesheets support behind a pref.

Comment 18

[Boris Zbarsky [:bzbarsky]]

OK.  Should we just go ahead and unpref :scope then?  Scoped stylesheets are m-c only, right?

Comment 19

[Cameron McCormack (:heycam)]

(In reply to Boris Zbarsky (:bz) from comment #18)
> OK.  Should we just go ahead and unpref :scope then?

Well... should we be taking into account how far advanced the relevant specification is?  :scope is in Selectors 4, which is a WD at the moment.  I don't remember what "rules" CSS WG members have in terms of unprefixed implementations.

As for the feature itself, I can't really see it changing much that would need us to have it be prefixed, really.

> Scoped stylesheets are m-c only, right?

Yes.

I realise now though that I did not do anything special to make :scope match the style scope element in scoped style sheets.  I guess I should do that...

Comment 20

[Jean-Yves Perrier [:teoli]]

Docs:
https://developer.mozilla.org/en-US/docs/Web/CSS/:scope (with a live sample ;-) )
and
https://developer.mozilla.org/en-US/docs/Mozilla/Firefox/Releases/20