1363088 - Inheritance logic in HasAuthorSpecifiedRules is slightly wrong for text-shadow

Status: RESOLVED FIXED

(Core :: CSS Parsing and Computation, enhancement, P3)

Description

[Matt Brubeck (:mbrubeck)]

This is a minor bug in nsRuleNode::HasAuthorSpecifiedRules that I noticed while porting its code to Stylo (bug 1349651).  nsRuleNode.cpp contains this comment:

>  // We need to be careful not to count styles covered up by user-important or
>  // UA-important declarations.  But we do want to catch explicit inherit
>  // styling in those and check our parent style context to see whether we have
>  // user styling for those properties.  Note that we don't care here about
>  // inheritance due to lack of a specified value, since all the properties we
>  // care about are reset properties.

However, the last sentence (and the associated code) became incorrect when bug 721750 added 'text-shadow' to the list of "properties we care about."

It's probably rare for this to affect any users. Because Gecko's UA stylesheets don't contain any UA-important declarations that set 'text-shadow', this bug is only triggered if there is a user stylesheet with a !important declaration that sets 'text-shadow'.

The effect of the bug is that the wrong 'text-shadow' style could be applied to selected text.

Comment 1

[Xidorn Quan [:xidorn] UTC+10]

Attachment: Bug 1363088 - Remove text-shadow handling from HasAuthorSpecifiedRules.

After bug 1401825, we no longer need the code for text-shadow anymore,
so we can just remove it.

Review commit: https://reviewboard.mozilla.org/r/188572/diff/#index_header
See other reviews: https://reviewboard.mozilla.org/r/188572/

Comment 2

[Cameron McCormack (:heycam)]

Comment on attachment 8917642 [details]
Bug 1363088 - Remove text-shadow handling from HasAuthorSpecifiedRules.

https://reviewboard.mozilla.org/r/188572/#review193830

::: layout/style/nsRuleNode.cpp:10514
(Diff revision 1)
> -
>    // properties in the SIDS, whether or not we care about them
>    size_t nprops = 0,
> -         backgroundOffset, borderOffset, paddingOffset, textShadowOffset;
> +         backgroundOffset, borderOffset, paddingOffset;
>  
>    // We put the reset properties the start of the nsCSSValue array....

Can drop this comment.

Comment 3

[Xidorn Quan [:xidorn] UTC+10]

Comment on attachment 8917642 [details]
Bug 1363088 - Remove text-shadow handling from HasAuthorSpecifiedRules.

Review request updated; see interdiff: https://reviewboard.mozilla.org/r/188572/diff/1-2/

Comment 4

[Xidorn Quan [:xidorn] UTC+10]

Attachment: Servo PR

Comment 5

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/8189460a08a7
Remove text-shadow handling from HasAuthorSpecifiedRules. r=heycam

Comment 6

[Sebastian Hengst [:aryx] (needinfo me if it's about an intermittent or backout)]

https://hg.mozilla.org/mozilla-central/rev/8189460a08a7