Layout Test fast/text/international/khmer-selection.html is crashing

[Per Arne Vollan]

The following layout test is failing on Windows:

fast/text/international/khmer-selection.html

Probable cause:

Unknown.

Flakiness Dashboard:

https://webkit-test-results.webkit.org/dashboards/flakiness_dashboard.html#showAllRuns=true&tests=fast%2Ftext%2Finternational%2Fkhmer-selection.html

[Per Arne Vollan]

Created attachment 362192 [details]
Patch

[Per Arne Vollan]

rdar://problem/47922356

[Myles C. Maxfield]

Comment on attachment 362192 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=362192&action=review

> Source/WebCore/platform/graphics/GlyphBuffer.h:161
> +        if (index >= m_offsetsInString->size())
> +            return GlyphBuffer::noOffset;

It looks like this happens any time complex text is underlined. I wish we could migrate Windows to ComplexTextController. I had a patch at https://bugs.webkit.org/show_bug.cgi?id=167954 but it never got finished.

Can we actually implement this feature instead of simply covering up its symptoms? We could make GlyphBuffer::add() not have any default arguments. Maybe I can do this today.

[Myles C. Maxfield]

Created attachment 362361 [details]
Alternative patch

[Myles C. Maxfield]

How about a patch like this? I don't know if it builds because I don't have a Windows machine, but it seems preferable to fix this problem by implementing the feature instead of failing gracefully.

[Per Arne Vollan]

(In reply to Myles C. Maxfield from comment #5)
> How about a patch like this? I don't know if it builds because I don't have
> a Windows machine, but it seems preferable to fix this problem by
> implementing the feature instead of failing gracefully.

Thanks, looks great, Myles! I am not sure why it is not building, probably just a small adjustment needed.

[Per Arne Vollan]

Created attachment 362519 [details]
Patch

[Per Arne Vollan]

(In reply to Per Arne Vollan from comment #7)
> Created attachment 362519 [details]
> Patch

This is Myles' patch.

[Per Arne Vollan]

Created attachment 362533 [details]
Patch

[Per Arne Vollan]

Created attachment 362552 [details]
Patch

[Per Arne Vollan]

Created attachment 362558 [details]
Patch

[Per Arne Vollan]

Created attachment 362613 [details]
Patch

[Brent Fulgham]

Comment on attachment 362613 [details]
Patch

Very nice! r=me.

[Per Arne Vollan]

(In reply to Brent Fulgham from comment #13)
> Comment on attachment 362613 [details]
> Patch
> 
> Very nice! r=me.

Thanks to Myles for creating the patch, and to Brent for reviewing :)

[WebKit Commit Bot]

Comment on attachment 362613 [details]
Patch

Clearing flags on attachment: 362613

Committed r241915: <https://trac.webkit.org/changeset/241915>

[WebKit Commit Bot]

All reviewed patches have been landed.  Closing bug.