1857130 - Add a WPT which checks that overscroll-behavior is respected on the <html> element

Status: RESOLVED FIXED

(Core :: Panning and Zooming, task, P2)

Description

[Botond Ballo [:botond]]

Chrome has a bug where it does not respect overscroll-behavior on the <html> element, only on the <body>.

To improve interop in this area, I would like to suggest adding a web platform test which checks for respecting overscroll-behavior on <html> specifically.

I think a way such a test could be formulated is to have an <iframe> with overscroll-behavior: contain on its <html> element, and check that scroll chaining from the iframe's contents to the enclosing document is successfully prevented.

Comment 1

[Botond Ballo [:botond]]

For now I created two manual testcases:

• https://theres-waldo.github.io/mozilla-testcases/overscroll-behavior-contain-iframe-html.html
• https://theres-waldo.github.io/mozilla-testcases/overscroll-behavior-contain-iframe-body.html

The STR for both is:

1. Scroll the page down to bring the iframe into view
2. Try to scroll the iframe upwards, and see if scroll chaining to scroll the enclosing page upwards works

Comment 2

[Timothy Nikkel (:tnikkel)]

Tested on Safari on macos.

Scrolling the iframe up does NOT scroll the page in overscroll-behavior-contain-iframe-html.html

Scrolling the iframe up does scroll the page in overscroll-behavior-contain-iframe-body.html

Comment 3

[Timothy Nikkel (:tnikkel)]

I was able to test on Safari an iOS device.

For both testcases, scrolling up the iframe overscrolled the iframe and did not scroll the page.

Comment 4

[Botond Ballo [:botond]]

(In reply to Timothy Nikkel (:tnikkel) from comment #3)

For both testcases, scrolling up the iframe overscrolled the iframe and did not scroll the page.

Huh, that's an interesting discrepancy betweeen macOS and iOS (or perhaps touchpad scrolling vs. touch scrolling).

I'd be curious to know whether the following two pages (which are just the same pages that are contained inside iframes in the previous test cases) allow pull-to-refresh in Safari on iOS:

• https://theres-waldo.github.io/mozilla-testcases/overscroll-behavior-contain-root-html.html
• https://theres-waldo.github.io/mozilla-testcases/overscroll-behavior-contain-root-body.html

Comment 5

[Botond Ballo [:botond]]

I proposed improving interop in this area for Interop 2024: https://github.com/web-platform-tests/interop/issues/560

We discussed the proposal in today's Interop 2024 triage meeting, and it was suggested that, to improve the chances of the proposal being accepted by other browser vendors, we should try to contribute these WPTs as soon as possible.

Emilio kindly offered to try turning the manual testcases from comment 1 into WPTs (needinfoing as requested).

Note that due to bug 1797215, Firefox will likely not pass these WPTs yet (but that's fine, getting them to pass can be part of the work we do during the Interop 2024 process).

Comment 6

[Botond Ballo [:botond]]

We have this existing WPT for overscroll-behavior, the new tests could be adaptations of this one where instead of a scrollable <div> we have a scrollable subdocument.

Comment 7

[Emilio Cobos Álvarez [:emilio]]

Attachment: Bug 1857130 - Add a test for overscroll-behavior working on root. r=botond

Comment 8

[Emilio Cobos Álvarez [:emilio]]

Does comment 7 look reasonable? Fails on Chrome here as expected.

Comment 9

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/5db6f03a7c10
Add a test for overscroll-behavior working on root. r=botond

Comment 10

[Web Platform Test Sync Bot [:wpt-sync] (Matrix: #interop:mozilla.org)]

Created web-platform-tests PR https://github.com/web-platform-tests/wpt/pull/42886 for changes under testing/web-platform/tests

Comment 11

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/8e02ea14e423
Add missing test metadata to use the compositor code-path for overscroll-behavior.

Comment 12

[Atila Butkovits]

Backed out for causing failures at overscroll-behavior-root.html.

Backout link: https://hg.mozilla.org/integration/autoland/rev/372618c6e03d17313a0c5f43d0054babb9e89074

Push where failures started: https://treeherder.mozilla.org/jobs?repo=autoland&selectedTaskRun=QvxTNKfPTfybWVcUyRoxcg.0&resultStatus=testfailed%2Cbusted%2Cexception%2Cretry%2Cusercancel&revision=6e5782df6da147ae5c916097b12efcfae7149b5c

Failure log: https://treeherder.mozilla.org/logviewer?job_id=434568361&repo=autoland&lineNumber=2947

Comment 13

[Web Platform Test Sync Bot [:wpt-sync] (Matrix: #interop:mozilla.org)]

Upstream PR was closed without merging

Comment 14

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/baf3d517ae40
Add a test for overscroll-behavior working on root. r=botond

Comment 15

[Noemi Erli[:noemi_erli]]

https://hg.mozilla.org/mozilla-central/rev/baf3d517ae40

Comment 16

[Web Platform Test Sync Bot [:wpt-sync] (Matrix: #interop:mozilla.org)]

Upstream PR merged by moz-wptsync-bot