1006326 - Enable 'box-decoration-break' by default

Status: VERIFIED FIXED

(Core :: CSS Parsing and Computation, enhancement)

Comment 1

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

What blocks enabling it on all builds (Nightly + Release)?

Comment 2

[Tim Nguyen :ntim]

I probably think it requires a tiny bit more testing.

Comment 3

[Mats Palmgren (inactive)]

The remaining piece is to implement layout of box-decoration-break:clone
for block margins: bug 1025669.  I don't know if that needs to block
enabling it though.  In particular, b-d-b should be fully working for
inlines as a replacement for -moz-background-inline-policy.

Comment 4

[Florian Bender]

Is there a particular reason this should only be enabled for Nightly, or can we enable it and let it ride the trains?

Comment 5

[Mats Palmgren (inactive)]

The implementation should be complete now, except for clip-path/clip/mask
in bug 988659.  Do we want to block on that bug?

Comment 6

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

I think we do *not* want to block, though I don't have a good sense of how hard it is.  (My guess is that it's hard-ish.)

Comment 7

[Mats Palmgren (inactive)]

Attachment: fix

Looks green so far...
https://tbpl.mozilla.org/?tree=Try&rev=ee02ec9cf863
https://tbpl.mozilla.org/?tree=Try&rev=a7c6113b1fb4

Comment 8

[Mats Palmgren (inactive)]

OK, so for FF32 I would recommend we uplift bug 1025669 (block margins),
bug 1031444 (bug fix) and bug 1031726 (clip:rect()) and then enable it
by default there too.

Does that seem reasonable?

Comment 9

[Mats Palmgren (inactive)]

https://hg.mozilla.org/integration/mozilla-inbound/rev/c6adaead7adf

Comment 10

[Mats Palmgren (inactive)]

BTW, should we post an "intent to ship" about this property?

Comment 11

[Wes Kocher (:KWierso) (Not reading bugmail; email directly if needed)]

https://hg.mozilla.org/mozilla-central/rev/c6adaead7adf

Comment 12

[Cameron McCormack (:heycam)]

(In reply to Mats Palmgren (:mats) from comment #10)
> BTW, should we post an "intent to ship" about this property?

Yes I believe we should do that with all new Web-exposed features.

Comment 13

[Mats Palmgren (inactive)]

OK, will do so as soon as dbaron responds to the n-i in comment 8.
The patches for Aurora are green on Try, fwiw:
https://tbpl.mozilla.org/?tree=Try&rev=98bad8e3d58f

Comment 14

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

(In reply to Mats Palmgren (:mats) from comment #8)
> OK, so for FF32 I would recommend we uplift bug 1025669 (block margins),
> bug 1031444 (bug fix) and bug 1031726 (clip:rect()) and then enable it
> by default there too.
> 
> Does that seem reasonable?

It's a little bit of a stretch of the purpose of Aurora, but I think it seems reasonable given that it avoids having the feature disappear for one release and then come back with a new name in the following one (right?).

Comment 15

[Mats Palmgren (inactive)]

Right, the uplift is intended to avoid that.  Great, so I'll request
approval on the patches in the relevant bugs as usual then.

Comment 16

[Mats Palmgren (inactive)]

Comment on attachment 8451167 [details] [diff] [review]
fix

Approval Request Comment
[Feature/regressing bug #]: 
We want to enable 'box-decoration-break' by default on Aurora
to provide an upgrade path for a property that were removed
(-moz-background-inline-policy).

[User impact if declined]: 
Web pages that use the old property will have some element's
background image displayed slightly wrong, and there
will be one cycle without an upgrade path to fix that.

[Describe test coverage new/current, TBPL]:
It's enabled by default on m-c.
Most of the 'box-decoration-break' patches are already on
Aurora but the feature is currently disabled by default.

[Risks and why]: minor risk

[String/UUID change made/needed]: none

Comment 17

[Lawrence Mandel [:lmandel] (use needinfo)]

Comment on attachment 8451167 [details] [diff] [review]
fix

Aurora+

Comment 18

[Lawrence Mandel [:lmandel] (use needinfo)]

Release note should include that box-decoration-break replaces -moz-background-inline-policy, which has been removed from Firefox 32.

Mats - Can you write a draft release note about this change? Is the following correct? If this is not a direct replacement it may be better to have a note about the removal and a note about the new property.

"-moz-background-inline-policy CSS property replaced with box-decoration-break"

As well, is the upgrade path documented somewhere that we can link to from the release notes?

Comment 19

[Mats Palmgren (inactive)]

I think the text on the MDN page might work as guidance for authors:
https://developer.mozilla.org/en-US/docs/Web/CSS/-moz-background-inline-policy
"This property has been standardized in css3-background with the name box-decoration-break, except that box-decoration-break applies to borders in addition to backgrounds.  The continuous value is equivalent to slice, and the each-box value is equivalent to clone. An equivalent to the bounding-box value was not included in the standard, and the functionality is likely to be removed when the standard feature is implemented."

The spec has changed since then, it's css-break, not css3-background.
http://dev.w3.org/csswg/css-break/#break-decoration

We should also update the current MDN page for b-d-b, which looks out of date:
https://developer.mozilla.org/en-US/docs/Web/CSS/box-decoration-break
(and link to it from the former page)

Comment 20

[Mats Palmgren (inactive)]

(btw, I'm updating those MDN pages a bit, while watching the tree...)

Comment 21

[Mats Palmgren (inactive)]

https://hg.mozilla.org/releases/mozilla-aurora/rev/bc2a45cc6a7e

Comment 22

[Mats Palmgren (inactive)]

I have updated the MDN pages.  I'd like to add a more prominent "obsolete"
warning on the -moz-background-inline-policy page but I don't know how to do
that.  I tried to link the CSS spec "CSS Fragmentation Module Level 3" on
the box-decoration-break page but MDN doesn't seem to recognize it as
a valid spec name and I don't know how to make it one.  (I've added
a plain external link there for now.)

Comment 23

[Jean-Yves Perrier [:teoli]]

Mats, I've added enough "warnings" on -moz-b-i-p I think. I also fixed the link on box-decoration-box and made slight modification to match our look and feel. I updated the text on Fx 32 for devs too.

I think we have an up-to-date doc for this property.

Mats, thanks for the very valuable help! Nice examples on the property doc!

Comment 24

[Petruta Horea [:phorea], Desktop QA]

Mats, I've tested using three samples from https://developer.mozilla.org/en-US/docs/Web/CSS/box-decoration-break using Firefox 32 beta 8 and latest Aurora (20140819004001) under Win 7 64-bit, Ubuntu 13.04 32-bit and Mac OSX 10.9.4.

Everything looks good except for the box-decoration-break-inline-extreme under Mac, where the characters are exceeding the circles. Please see http://i.imgur.com/O4IbnFa.png.

Is this related to this issue? Thanks

Comment 25

[Mats Palmgren (inactive)]

(In reply to Petruta Rasa [QA] [:petruta] from comment #24)
> Everything looks good except for the box-decoration-break-inline-extreme
> under Mac, where the characters are exceeding the circles. Please see
> http://i.imgur.com/O4IbnFa.png.

Yeah, I think that can happen with extreme border-radius values.
I guess we can avoid that and make it look better by adding some
padding, say padding:10px.  Feel free to update the example and
add a new screenshot on the wiki-page ;-)

Comment 26

[Petruta Horea [:phorea], Desktop QA]

Adding padding:5px makes it look better on Mac too, thanks. 

Marking as verified as per comment 24.