Simplify popover=hint behaviours & related spec fixes by jakearchibald · Pull Request #12345 · whatwg/html

jakearchibald · 2026-04-08T13:45:02Z

Commit message:

Simplify popover=hint behaviors

- Showing a hint popover doesn't hide auto popovers.
- Showing a hint popover hides non-parent hint popovers.
- Clicking outside popovers consistently hides them.
- Hiding an auto popover does not hide unrelated hint popovers.
- Showing an auto popover as a child of a hint popover downgrades the auto popover to a hint.
- Showing a popover during the show or hide of another popover is no longer allowed.

At least two implementers are interested (and none opposed):
- Mozilla
- Google
Tests are written and can be reviewed and commented upon at:
- Implement new/revised popover=hint behavior web-platform-tests/wpt#59237
Implementation bugs are filed:
- Chromium: https://crbug.com/499019927 (Also, PRs are already up.)
- Gecko: https://bugzilla.mozilla.org/show_bug.cgi?id=2034661
- WebKit: Not required. This will be picked up with general popover hint work.
Corresponding HTML AAM & ARIA in HTML issues & PRs: Not required.
MDN issue is filed: Not required.
The top of this comment includes a clear commit message to use.

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

Fixes #12304.

Fixes #12346.

Fixes #12355.

Fixes #12356.

Add stuff to infra & use it
Decide on & spec auto-in-hint behaviour
Decide on & spec what happens with popovers shown during beforetoggle-hide.
Review new tests & add more if needed
Apply wrapping

/form-elements.html ( diff )
/infrastructure.html ( diff )
/interactive-elements.html ( diff )
/popover.html ( diff )

jakearchibald · 2026-04-08T14:01:09Z

I'll sort out the wrapping after reviews & changes.

lukewarlow · 2026-04-08T14:14:41Z

Btw https://github.com/domfarolino/specfmt is quite useful for the wrapping.

jakearchibald · 2026-04-08T15:20:38Z

@lukewarlow haha your deleted comment did reveal a bug! It wasn't the return false that was wrong, but I was missing a return true.

jakearchibald · 2026-04-08T15:29:29Z

Edit: I've broken this out into #12355

av1.mp4

@mfreed7 sorry for another video, but I don't think I'd be able to describe it well. What do you see as the intended behaviour here?

https://random-stuff.jakearchibald.com/bug-repros/popover-show-on-hide-warning/ - here's the demo page.

Edit: I'm not convinced my spec totally solves this either, as hiding a popover hides child popovers, which would include the new ones added, and they'd be hidden with events. Maybe.

jakearchibald · 2026-04-09T12:00:41Z

@mfreed7 can you create a PR for your tests so far?

For whatwg/html#12345.

keithamus · 2026-04-10T09:04:38Z

+       <span>"<code>InvalidStateError</code>"</span> <code>DOMException</code>.</p></li>
+
+       <li><p>Return false.</p></li>
+      </ol>


jakearchibald · 2026-04-17T15:19:46Z

@keithamus and @mfreed7, hopefully this is it in terms of the behaviour. Aside from editorial stuff, I've changed:

Light dismiss (click behaviour) is changed so it correctly closes unrelated auto popovers if a hint is clicked.
Topmost popover ancestor algorithm should be doing the correct thing now.
Opening a hint popover within an auto popover now downgrades the popover to hint, and allows it to open.
Showing a popover during the show/hide of another is no longer allowed.

On that last point, I was pretty heavy-handed, and applied it to all popovers, not just auto/hint. Otherwise, it gets tricky if the popover type changes.

Thank you for all the reviews so far. Up for one more?

I'll take a look at the tests.

mfreed7 · 2026-04-17T17:20:01Z

@keithamus and @mfreed7, hopefully this is it in terms of the behaviour.

Thanks again for taking this on!

Opening a hint popover within an auto popover now downgrades the popover to hint, and allows it to open.

This bit is not yet represented in the WPTs, FYI. I don't think I can get to it today, but maybe. Let me know if you edit the WPTs in the meantime. All of the rest should be represented (modulo my note below).

On that last point, I was pretty heavy-handed, and applied it to all popovers, not just auto/hint. Otherwise, it gets tricky if the popover type changes.

I think that's fine. Exceptions are better than confusing situations - they lead to the well lit path.

Thank you for all the reviews so far. Up for one more?

I'll look right now.

I'll take a look at the tests.

Thanks! Note that this set of changes landed in Chromium, but hasn't been put up as a WPT PR yet. I think our infra is having a problem. I've pinged them.

mfreed7 · 2026-04-17T19:39:32Z

Thank you for all the reviews so far. Up for one more?

I'll look right now.

I think the new changes look good, modulo the one I re-opened and commented on. Otherwise, great! I'm getting started on the new/changed WPTs corresponding to the auto-downgrades-to-hint and "loop" prevention stuff.

mfreed7 · 2026-04-17T21:11:43Z

Complete aside: it's cool and it's also a problem that you've grabbed PR #12345. My LLM wrote that into a comment, and I just naturally assumed it hallucinated the number.

jakearchibald · 2026-04-20T18:32:21Z

@mfreed7

Complete aside: it's cool and it's also a problem that you've grabbed PR #12345. My LLM wrote that into a comment, and I just naturally assumed it hallucinated the number.

Yes! It was really satisfying to grab #12345. Even more-so because, when I noticed the original issue was #12304, I thought "ohhhh, #12345 will be soon! I wonder what that will be".

mfreed7

LGTM, and I'm working on putting up the corresponding WPT changes.

mfreed7 · 2026-04-23T20:47:59Z

LGTM, and I'm working on putting up the corresponding WPT changes.

Ok, I've implemented the latest things in Chromium (auto downgrades to hint, and all of the togglepopover reentrancy stuff) and adjusted WPTs accordingly. Due to the first WPT being stuck in manual review, the next two can't even be uploaded as PRs yet. So just to track the changes in one place, here are all three sets:

Implement new/revised popover=hint behavior web-platform-tests/wpt#59237
https://crrev.com/c/7765209 (landed, but waiting on above PR)
https://crrev.com/c/7787494 (still in Chromium review as of now)

jakearchibald · 2026-04-24T00:14:46Z

@mfreed7 a lovely bit of teamwork! I'm happy for this to land if you are?

mfreed7 · 2026-04-24T15:53:38Z

@mfreed7 a lovely bit of teamwork! I'm happy for this to land if you are?

Totally agree - thanks for raising these issues, explaining them so clearly, and then working through the solutions. This feature got better/cleaner as a result.

LGTM to land this.

This patch updates the popover implementation to align with recent HTML spec changes, specifically regarding reentrancy protection and nested popover types. See the conversation in the spec PR: whatwg/html#12345 1. Strict Reentrancy Protection: Documents now maintain a `popover_showing` boolean and a `popover_hiding_nesting_count` integer to prevent concurrent popover toggles. If `showPopover()` is called while a popover is actively showing or hiding, a `DOMExceptionCode::kInvalidStateError` is immediately thrown. Stack-allocated `ScopedPopoverShowing` and `ScopedPopoverHiding` RAII helpers have been added to safely manage this state during `ShowPopoverInternal` and `HidePopoverInternal`. 2. Downgrading `popover=auto` to `popover=hint`: Previously, attempting to open an `auto` popover nested inside a `hint` popover threw an `InvalidStateError`. The spec now dictates that the `auto` popover should be permitted to open but with its effective type downgraded to `hint`. `ShowPopoverInternal` has been updated to omit the exception and coerce the incoming popover into the `hint_stack` so it appropriately assumes hint light-dismissal behaviors. Check invariants in `HideAllPopoversUntil` have been relaxed to handle this downgraded state safely. Tests in `external/wpt/html/semantics/popovers` have been updated to reflect the new expected behaviors. Bug: 499019927 Change-Id: Ibd6af063310585b9044de63a06e36ffd79d011d4 Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/7787494 Auto-Submit: Mason Freed <masonf@chromium.org> Reviewed-by: Joey Arhar <jarhar@chromium.org> Commit-Queue: Mason Freed <masonf@chromium.org> Cr-Commit-Position: refs/heads/main@{#1620601}

Co-authored-by: Copilot <copilot@github.com>

jakearchibald · 2026-04-27T22:57:14Z

@annevk looks like we're happy for this to land unless there's anything I'm missing?

There have been a few changes since you last reviewed (sorry), in case you want to review again.

(omg @domfarolino thanks so much for specfmt)

annevk · 2026-04-28T18:25:04Z

@jakearchibald OP appears incomplete. Note that after each edit (including checking a checkbox so best to not use the UI for that) you have to wait for the bot to update it as it will overwrite you otherwise. Also a bit unclear what the status of the tests is.

jakearchibald · 2026-04-29T13:40:54Z

@mfreed7 are the tests complete?

@annevk aside from the tests (waiting for @mfreed7's feedback), I've updated the OP.

mfreed7 · 2026-04-29T15:20:17Z

@mfreed7 are the tests complete?

This comment (#12345 (comment)) is still the state of things. I've left reply comments on the first PR, and the second two are still queued up in Chromium's infra waiting to be uploaded.

As far as I'm concerned, yes, the new WPTs are all good. But I'm biased - I wrote them. Perhaps it'd be best to land all three of those PRs (which given the review hangups will likely take days) as-is, and then we can sort out any nits about the resulting state of tests?

jakearchibald added 4 commits April 8, 2026 13:45

Show popover fixed

04c3483

The rest of the owl

f4714ea

No need to set hideUntil to document

3bca74f

Another document set

dc41ca8

jakearchibald commented Apr 8, 2026

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jakearchibald marked this pull request as ready for review April 8, 2026 14:01

jakearchibald requested review from keithamus, lukewarlow and mfreed7 April 8, 2026 14:01

Missing return true

4518fd0

jakearchibald mentioned this pull request Apr 8, 2026

What should happen if you open an auto popover 'within' a hint popover? #12346

Open

annevk reviewed Apr 9, 2026

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This was referenced Apr 9, 2026

Add list slice whatwg/infra#706

Merged

Add list reverse whatwg/infra#707

Merged

jakearchibald commented Apr 9, 2026

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jakearchibald added 5 commits April 9, 2026 11:38

Minor changes

e345ff0

Hint first, and make it clear the conditions are exclusive

8f4f8fd

Actually remove the TODO lol

31a54ee

Create algo for closing hint then auto popovers

afc6003

Fixing silly mistakes

d2fd3f5

jamesnw mentioned this pull request Apr 9, 2026

Update popover=hint to match spec changes oddbird/popover-polyfill#275

Open

keithamus mentioned this pull request Apr 9, 2026

Should the popoverList in "hide popover stack until" and "close entire popover list" be dynamically updated? #11007

Open

annevk pushed a commit to whatwg/infra that referenced this pull request Apr 10, 2026

Add list reverse

7f8c8ee

For whatwg/html#12345.

Don't hide autos if endpoint is in the hint stack

657f638

keithamus reviewed Apr 10, 2026

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jakearchibald added 10 commits April 17, 2026 12:00

Change arg order of popover hide

7a71186

Set hint stack branch earlier

470b816

Add missing 'otherwise's

f6816de

options to arguments

2dbb9bf

Rename cleanupShowingFlag to cleanupShowingSteps

4937655

Correct popover click behavior

3e4a889

Fix topmost popover ancestor

acfe14a

Allow auto within hint by downgrading to hint

0f6701f

Disallow showing a popover while another is showing

f99432c

Prevent showing a popover during the show or hide of another popover

7ca5f3d

mfreed7 reviewed Apr 17, 2026

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jakearchibald commented Apr 18, 2026

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jakearchibald commented Apr 18, 2026

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mfreed7 approved these changes Apr 23, 2026

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mfreed7 reviewed Apr 24, 2026

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jakearchibald and others added 2 commits April 27, 2026 18:52

Correct handling of throw

c6a01ba

Co-authored-by: Copilot <copilot@github.com>

Wrap

d70b0a8

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