Bug 150006 – REGRESSION(r182192): Ligatures do not interact correctly with SHY in some fonts

• Component: Text
• Status: RESOLVED FIXED

[Myles C. Maxfield]

Created attachment 262836 [details]
Reduction

See attached reduction.

[Myles C. Maxfield]

Created attachment 262837 [details]
Reduction font

[Myles C. Maxfield]

Occurs on iOS and OS X

[Myles C. Maxfield]

Problem occurs on El Capitan, but does not occur on Yosemite.

[Myles C. Maxfield]

Disregard my last comment.

Problem occurs on shipping Safari on Yosemite.

On ToT Safari on Yosemite, font-variant-ligatures: common-ligatures; fixes the problem.

Because on shipping Safari, the problem goes away when you select the text, this is likely a disagreement between our fast and complex text paths. The previous evidence about font-variant-ligatures seems to agree with this (because font-variant-ligatures forces us onto our complex path)

[Myles C. Maxfield]

(In reply to comment #4)
> Disregard my last comment.
> 
> Problem occurs on shipping Safari on Yosemite.
> 
> On ToT Safari on Yosemite, font-variant-ligatures: common-ligatures; fixes
> the problem.
> 
> Because on shipping Safari, the problem goes away when you select the text,
> this is likely a disagreement between our fast and complex text paths. The
> previous evidence about font-variant-ligatures seems to agree with this
> (because font-variant-ligatures forces us onto our complex path)

Same thing on El Capitan.

[Myles C. Maxfield]

I caused this in r182192.

I'm shifting glyphs and advances, but not the rest of GlyphBuffer's contents.

[Myles C. Maxfield]

Created attachment 262838 [details]
Option 1

[WebKit Commit Bot]

Attachment 262838 [details] did not pass style-queue:


ERROR: Source/WebCore/ChangeLog:15:  You should remove the 'No new tests' and either add and list tests, or explain why no new tests were possible.  [changelog/nonewtests] [5]
Total errors found: 1 in 3 files


If any of these errors are false positives, please file a bug against check-webkit-style.

[Myles C. Maxfield]

Created attachment 262839 [details]
Option 1

[Myles C. Maxfield]

Created attachment 262840 [details]
Option 2

[Myles C. Maxfield]

Option 2 is preferable.

[Alexey Proskuryakov]

Comment on attachment 262840 [details]
Option 2

View in context: https://bugs.webkit.org/attachment.cgi?id=262840&action=review

> Source/WebCore/ChangeLog:14
> +        However, now that <rdar://problem/20230073> is fixed, we don't need to perform this filter in
> +        the first place.

Please make sure that all Mavericks bots (including EWS) have the appropriate security update installed.

I'm pretty sure that they do not, so landing this will make the original problem occur again.

[Myles C. Maxfield]

Committed r190891: <http://trac.webkit.org/changeset/190891>