Bug 210954 – Use @isUndefinedOrNull instead of abstract equality with null

• Status: RESOLVED
• Resolution: FIXED
• Component: JavaScriptCore

[Alexey Shvayka]

Use @isUndefinedOrNull instead of abstract equality with null

[Alexey Shvayka]

Created attachment 397430 [details]
Patch

[Yusuke Suzuki]

Comment on attachment 397430 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=397430&action=review

r=me with comment.

> Source/JavaScriptCore/ChangeLog:14
> +        b) Replaces 3 `!= @undefined` and 7 `!= null` comparisons with @isUndefinedOrNull()
> +        as only the latter is correct with [[IsHTMLDDA]] aka MasqueradesAsUndefined objects [2].

Can you add a test with IsHTMLDDA? jsc shell has IsHTMLDDA mechanism so we can write a test for MasqueradesAsUndefined with JSC shell.

[Alexey Shvayka]

Created attachment 399669 [details]
Patch

Rebase JSTests/test262/expectations.yaml and set reviewer.

[Alexey Shvayka]

(In reply to Yusuke Suzuki from comment #2)
> Can you add a test with IsHTMLDDA? jsc shell has IsHTMLDDA mechanism so we
> can write a test for MasqueradesAsUndefined with JSC shell.

I've added test262 coverage for all the comparisons fixed by this patch (r259587 introduced proper $262.IsHTMLDDA).
These tests will be also beneficial for non-mainstream engines like Hermes, which, judging by source code
(https://github.com/facebook/hermes/blob/b6530ae7e25604839c33b60261fb2832f49ca464/lib/InternalBytecode/String.js#L673),
may have the same bug.

[Alexey Shvayka]

Comment on attachment 399669 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=399669&action=review

> JSTests/test262/expectations.yaml:11
>  test/annexB/built-ins/String/prototype/replaceAll/custom-replacer-emulates-undefined.js:

This test is wrong. Upstream fix: https://github.com/tc39/test262/pull/2626.

[EWS]

Committed r262017: <https://trac.webkit.org/changeset/262017>

All reviewed patches have been landed. Closing bug and clearing flags on attachment 399669 [details].

[Radar WebKit Bug Importer]

<rdar://problem/63502823>