Bug 309525 – [macOS Release] media/video-webkit-playsinline.html is a flaky text failure

• Status: NEW
• Component: Media

[Diego De La Toba]

media/video-webkit-playsinline.html is a flaky text failure on macOS release.


HISTORY:
https://results.webkit.org/?suite=layout-tests&test=media%2Fvideo-webkit-playsinline.html


DIFF:
--- /Volumes/Data/worker/Apple-Tahoe-Release-AppleSilicon-WK2-Tests/build/layout-test-results/media/video-webkit-playsinline-expected.txt
+++ /Volumes/Data/worker/Apple-Tahoe-Release-AppleSilicon-WK2-Tests/build/layout-test-results/media/video-webkit-playsinline-actual.txt
@@ -11,7 +11,7 @@
 RUN(video.play())
 EVENT(playing)
 EXPECTED (internals.isChangingPresentationMode(video) == 'false') OK
-EXPECTED (video.webkitDisplayingFullscreen == 'true') OK
+EXPECTED (video.webkitDisplayingFullscreen == 'true'), OBSERVED 'false' FAIL
 RUN(internals.settings.setInlineMediaPlaybackRequiresPlaysInlineAttribute(false))
 RUN(video.removeAttribute("webkit-playsinline", ""))
 EVENT(canplaythrough)


DIFF URL:
https://build.webkit.org/results/Apple-Tahoe-Release-AppleSilicon-WK2-Tests/308907@main%20(2289)/media/video-webkit-playsinline-pretty-diff.html


REPRODUCTION:
I was able to reproduce on macOS with the following:

run-webkit-tests --no-build --no-retry --no-show-results --exit-after-n-failures=1 --expect-pass --iterations=1000 --force --release media/video-webkit-playsinline.html

I am going to mark expectations as pass fail while this pends investigation.

[Radar WebKit Bug Importer]

<rdar://problem/172127512>

[Diego De La Toba]

Test gardening pull request: https://github.com/WebKit/WebKit/pull/60220

[EWS]

Test gardening commit 308941@main (b9631a1202de): <https://commits.webkit.org/308941@main>

Reviewed commits have been landed. Closing PR #60220 and removing active labels.

[Diego De La Toba]

Based on my analysis, Test 2 fails because Test 1's video is asynchronously exiting fullscreen when Test 2 attempts to enter fullscreen. The document-level m_isAnimatingFullscreen flag is still true, causing canEnterVideoFullscreen() to return false. Test 2's video never enters fullscreen, resulting in the text diff.

What could be happening is WebKit's fullscreen system doesn't properly handle rapid fullscreen enter/exit from different video elements. 

A test development fix for this is to add explicit waits for isChangingPresentationMode and webkitDisplayingFullscreen to become false. This forces all states to be settled before we proceed to the next test.

[Diego De La Toba]

Pull request: https://github.com/WebKit/WebKit/pull/60222