Intent to Ship: Shadow DOM and Custom Elements

[smaug]

I'm planning to keep Shadow DOM and Custom Elements turned on on beta/release builds.
Target release is Firefox 63.
prefs are dom.webcomponents.customelements.enabled and dom.webcomponents.shadowdom.enabled.

Custom elements has been enabled in Nightly since January and Shadow DOM since late May.

Bugs:
https://bugzilla.mozilla.org/show_bug.cgi?id=1471947 (Shadow DOM)
https://bugzilla.mozilla.org/show_bug.cgi?id=1471948 (Custom Elements)

Even though the APIs are totally distinct, web pages expect either neither be there or both, so they
need to ship together.



-Olli

[David Burns]

Do we have sufficient tests for this to guarantee webcompat and interop
with other browsers?

David

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[smaug]

On 08/13/2018 12:25 PM, David Burns wrote:
> Do we have sufficient tests

There are some tests, but as always, not enough. And there are areas which are not spec'ed, like
dir-attribute handling on HTML elements with Shadow DOM and session history of iframes which are in shadow DOM.

> for this to guarantee webcompat and interop

> with other browsers?CustomElements is easier, since it doesn't really change much, just adds a way to add couple of callbacks to user defined elements.
And the behavior of those callbacks is somewhat easy to test.

Shadow DOM is trickier, since the specs aren't always quite up-to-date, or leave things undefined.

Also, in general web components are relatively rarely used feature. Google has been a big user, but it relies on
v0 implementations, meaning basically Blink, and uses polyfills with other browsers.

So, there is definitely some risk breaking web sites, but there isn't too much we can do other than trying to ship.

[darin....@gmail.com]

When it ships in version 63 will shadowdom and webcomponent be shipped disabled or enabled by default? The beta is throwing me off.

Thank you,
-Darin

[smaug]

Current beta is FF62. The aim is to ship in FF63, which goes to beta early September.

[smaug]

And "ship" means, enabled by default. Most of the code has been there for several months even in release builds, but just disabled.

[Eric Shepherd (Sheppy)]

I, for one, would like to say: "Huzzah!"

On Fri, Aug 10, 2018 at 4:54 PM, <mustafas...@gmail.com> wrote:

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--

Eric Shepherd
Senior Technical Writer
Mozilla
Blog: http://www.bitstampede.com/
Twitter: http://twitter.com/sheppy
Check my Availability <https://freebusy.io/eshe...@mozilla.com>

[darin....@gmail.com]

On Wednesday, August 15, 2018 at 5:56:06 AM UTC-5, smaug wrote:
> On 08/15/2018 01:54 PM, smaug wrote:

> > On 08/14/2018 09:43 PM, darin wrote:
> >> When it ships in version 63 will shadowdom and webcomponent be shipped disabled or enabled by default? The beta is throwing me off.
> >>
> >> Thank you,
> >> -Darin
> >>
> >
> >
> > Current beta is FF62. The aim is to ship in FF63, which goes to beta early September.
>
>
> And "ship" means, enabled by default. Most of the code has been there for several months even in release builds, but just disabled.

Why does https://caniuse.com/#feat=shadowdomv1 show Firefox 63 show not supported by default?

[smaug]

No idea. I don't know who maintains caniuse and when the they update it. Please report to them that they may want to update the page.

[Chris Peterson]

On 2018-08-15 9:04 AM, smaug wrote:
>>
>> Why does https://caniuse.com/#feat=shadowdomv1 show Firefox 63 show
>> not supported by default?
>>
>
>
>
> No idea. I don't know who maintains caniuse and when the they update it.
> Please report to them that they may want to update the page.

The caniuse data is manually maintained on GitHub:

https://github.com/Fyrd/caniuse