Add the inert attribute and tweak definition of inert subtrees

[nt1m]

Based on work in #4288 by Alice Boxhall.

Added the inert attribute and tweaked inert subtrees definition.

• At least two implementers are interested (and none opposed):
  • Chromium
  • WebKit
• Tests are written and can be reviewed and commented upon at:
  • https://github.com/web-platform-tests/wpt/tree/master/inert
• Implementation bugs are filed:
  • Chrome: https://bugs.chromium.org/p/chromium/issues/detail?id=692360
  • Firefox: https://bugzilla.mozilla.org/show_bug.cgi?id=1655722
  • Safari: https://bugs.webkit.org/show_bug.cgi?id=165279

(See WHATWG Working Mode: Changes for more details.)

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/acknowledgements.html ( diff )
/index.html ( diff )
/interaction.html ( diff )

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/dom.html ( diff )
/index.html ( diff )
/indices.html ( diff )
/infrastructure.html ( diff )
/interaction.html ( diff )

[josepharhar]

It looks like there are WPTs here? https://wpt.fyi/results/inert
Here is the chrome bug: https://bugs.chromium.org/p/chromium/issues/detail?id=692360

[nt1m]

@josepharhar Updated, thanks. I'm hoping to get to updating this PR in the next couple of weeks.

[bkardell]

related #4288

[annevk]

@nt1m did you see #4288 (review) by @rniwa?

How does this relate to @alice's work? Was/should there be some coordination?

[nt1m]

@nt1m did you see #4288 (review) by @rniwa?

Yes, I described my rationale for using flat tree descendants in #7134 (comment)

How does this relate to @alice's work?

This is a newer version of it, I created a new PR to not have all the old comments.

Was/should there be some coordination?

There is an email thread going around about shipping inert with @emilio, @smfr, me, @chrishtr and @mfreed7. Alice is no longer involved afaik.

[mfreed7]

This generally LGTM. It'd be good if @josepharhar also took a look, given that he's implementing it in Chromium.

[alice]

There is an email thread going around about shipping inert with @emilio, @smfr, me, @chrishtr and @mfreed7. Alice is no longer involved afaik.

I'm not dead :) A little credit for the years of work I did on this would be nice.

[nt1m]

@alice Thanks for all your work done on the topic! I did re-use some parts of #4288, but also re-wrote quite a bit of it too, I hope that's ok with you.

Didn't mean to discredit your work, but I did hear that you moved on to different projects. Feel free to leave feedback if you have any, your expertise is welcome :)

[alice]

Starting an entirely new PR without any reference to the old one, and putting your name and not mine in the acknowledgements doesn't look like you didn't mean not to acknowledge me.

I trust the reviewers to do a good job reviewing the text here - I've said my piece on the design of the feature in the past, rehashing that seems pointless at this stage.

[nt1m]

@alice I apologize for not asking before making a new PR, someone from Google during the CSSWG meeting said you were working on other projects, and I really wanted to get inert shipped over the finish line without having to iterate over a stale PR that I do not own.

If you're referring to my name in the "acknowledgements" section, this is because it's a requirement when making a first PR: https://github.com/whatwg/html/blob/main/CONTRIBUTING.md#pull-requests

Please add your name to the Acknowledgments section (search for <!-- ACKS) in your first pull request, even for trivial fixes. The names are sorted lexicographically.

Your name was already in this section before making this PR: "Alice Boxhall": https://html.spec.whatwg.org/multipage/acknowledgements.html#acknowledgments

I added credit in the description of this PR (sorry for not doing this in the first place). I'm happy to remove my name if you prefer, (and/or) iterating over the old PR. Please let me know if there's something else I can do.

[annevk]

@nt1m thanks for the reference on using flat trees. That makes sense to me given pointer-events:none. Since you work at the same org, I take it you ran this by @rniwa as well?

[annevk]

Note to maintainers: let's try to make sure the final commit contains

Co-authored-by: Alice Boxhall <aboxhall@chromium.org>

at the end.

[nt1m]

@annevk I've added the link to pointer-events: none; which I think should remove the need for an example :) Please let me know if there's anything else to address.

[annevk]

I thought the idea was that both pointer-events:none and this would share a definition in a css3-ui? (I also reopened the discussion on focus above.)

I still think keeping the example would be useful for readers not deeply familiar with the subject matter. It was also rather short.

[annevk]

Overall this looks good to me. I mainly have editorial nits and suggestions.

[Loirooriol]

Is there anything else to do here? I'd want this to land in order to send an intent to ship for Blink.

[domenic]

LGTM, but @annevk has been the primary reviewer so he should confirm before we merge.

[annevk]

Thanks again @alice and @nt1m for making this happen! And everyone else who took part in design, review, implementation, and testing. It took a while, but the inert attribute is now officially part of HTML. 🎉