Bug 157283 – Indexing CSSStyleDeclaration object with out-of-range index should return undefined

• Component: Bindings
• Status: RESOLVED FIXED

[Chris Dumez]

Indexed property getters returning a DOMString should not return undefined for out of bound access. Instead, it should behave like regular operations returning a DOMString or DOMString attribute getters. Namely, it should:
- Return null if the returned DOMString type is nullable
- Return the empty string otherwise

Firefox and Chrome seem to behave correctly but WebKit always returns undefined in this case.

[Chris Dumez]

Created attachment 277943 [details]
Patch

[Darin Adler]

Comment on attachment 277943 [details]
Patch

What is the compatibility risk to fixing this? How did you notice this?

[Chris Dumez]

(In reply to comment #2)
> Comment on attachment 277943 [details]
> Patch
> 
> What is the compatibility risk to fixing this? How did you notice this?

I noticed it somewhat randomly when writing a layout test. I would assume the compatibility risk is very low as developers tend to not do out of range indexing, they usually access the length and iterate from 0 to length - 1. Also, Firefox behaves this way.

[WebKit Commit Bot]

Comment on attachment 277943 [details]
Patch

Clearing flags on attachment: 277943

Committed r200358: <http://trac.webkit.org/changeset/200358>

[WebKit Commit Bot]

All reviewed patches have been landed.  Closing bug.