Empty files should not succeed in loading (as WebVTT)

[Ahmad Saleem]

Hi Team,

While going through Blink's commit, I came across another potential merge:

Blink Commit: https://chromium.googlesource.com/chromium/src.git/+/0983d4b64cb5f519684f773daa27b2ac9b8f8688

WebKit Source: https://searchfox.org/wubkat/source/Source/WebCore/loader/TextTrackLoader.cpp#120

WPT Test Case: https://wpt.fyi/results/webvtt/parsing/file-parsing/signature-invalid.html?label=master&label=experimental&aligned=&q=signature

WPT Test Case Live Link: http://wpt.live/webvtt/parsing/file-parsing/signature-invalid.html

^ It is about first failure - 'signature, empty'.

Just wanted to raise, so we can fix it. Adding "WPTImpact" and "BrowserCompat" tags.

Thanks!

[Radar WebKit Bug Importer]

<rdar://problem/114118292>

[Ahmad Saleem]

NOTE - Doing 1-1 Blink Merge leads to two WPT regressions:

html/semantics/embedded-content/media-elements/track/track-element
/track-add-remove-cue.html

and

html/semantics/embedded-content/media-elements/track/track-element/track-text-track-cue-list.html

___

PR attempt: https://github.com/WebKit/WebKit/pull/16863

____

NOTE: We should sync 'webvtt' and look into why the tests are timing out and fix it.

Still investigating but closing my PR for time being.

[Anne van Kesteren]

I was thinking of fixing this in TextTrackLoader::notifyFinished by changing

if (m_cueParser)
    m_cueParser->fileFinished();

to

if (m_cueParser)
    m_cueParser->fileFinished();
else
    m_state = Failed;

but I'm not sure if that would similarly regress tests.

However, looking closely at your commit it seems that WebKit would still invoke processNewCueData for the non-Failed states whereas Chromium would not (at least not at that point in time).

Syncing webvtt WPT is probably a good next step here. I can maybe do that today between meetings.

[Kueno]

@Ahmad Saleem @Anne van Kesteren

Are you working on this issue? If not, I'd be happy to take it over.

[Ahmad Saleem]

(In reply to Kueno from comment #4)
> @Ahmad Saleem @Anne van Kesteren
> 
> Are you working on this issue? If not, I'd be happy to take it over.

I am not. Go ahead and take it. You are doing amazing job!! We all really appreciate it.

[Kueno]

Pull request: https://github.com/WebKit/WebKit/pull/19401

[EWS]

Committed 269646@main (d40154a4fe8f): <https://commits.webkit.org/269646@main>

Reviewed commits have been landed. Closing PR #19401 and removing active labels.