1041128 - Duplicate property name in object literal is allowed in ES6 strict mode

Status: RESOLVED FIXED

(Core :: JavaScript Engine, defect)

Description

[ziyunfei]

User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_9_3) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/38.0.2094.0 Safari/537.36

Steps to reproduce:

js> (function(){"use strict";({1:1,1:1})}())




Actual results:

SyntaxError: property name 1 appears more than once in object literal



Expected results:

This code shouldn't throw any more

Comment 1

[guptha]

Attachment: Patch to allow duplicate properties in object literals v1

This patch does not actually remove the failing test cases. I'll add a follow-up patch once Waldo's patch goes in.

Comment 2

[guptha]

Attachment: Patch to allow duplicate properties in object literals part 2 v1

Waldo, the diff is a bit wonky in update-test262.sh (shows your changes as mine) - I will make sure that once your patch lands, mine applies on top of it.

Comment 3

[Jason Orendorff [:jorendorff]]

Comment on attachment 8470234 [details] [diff] [review]
Patch to allow duplicate properties in object literals v1

Review of attachment 8470234 [details] [diff] [review]:
-----------------------------------------------------------------

This also gets rid of the "extra warnings"-mode warning about duplicate properties. I'm a little ambivalent because it means you'll be able to (for example) declare a large class, accidentally declare a method twice, and get no warning whatsoever.

But on consideration I think we should let it go.

Comment 4

[guptha]

Attachment: Patch to allow duplicate properties in object literals v2

Addressed review comments in bug 924672.

Comment 5

[Jeff Walden [:Waldo]]

Comment on attachment 8472521 [details] [diff] [review]
Patch to allow duplicate properties in object literals part 2 v1

Review of attachment 8472521 [details] [diff] [review]:
-----------------------------------------------------------------

Flat-out test removals makes for a nice, simple patch.

::: js/src/tests/update-test262.sh
@@ +133,5 @@
>  
> +# Apply a very narrow set of post-fixes to tests that haven't yet been updated
> +# for spec changes, or where we're experimenting with semantics that disagree
> +# with those in test262.  See below: this isn't every test we don't pass!
> +patch -d "${js_src_tests_dir}" -p4 < ./poison-pill-changes.diff

Remove this line, I'll merge it into these changes if you land first.  (Or you can do likewise if I land first.)

Comment 6

[guptha]

Attachment: Patch to allow duplicate properties in object literals v1

Merged Waldo's changes in. Unified the two parts to create a single diff.

Comment 7

[guptha]

https://tbpl.mozilla.org/?tree=Try&rev=d8816fa5f641

Comment 8

[Carsten Book [:Tomcat]]

https://hg.mozilla.org/integration/mozilla-inbound/rev/38b0ac8e7280

Comment 9

[Wes Kocher (:KWierso) (Not reading bugmail; email directly if needed)]

https://hg.mozilla.org/mozilla-central/rev/38b0ac8e7280

Comment 10

[Florian Scholz (Open Web Docs)]

Mentioned on these pages:

* https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Object_initializer#Duplicate_property_names

* https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Strict_mode/Transitioning_to_strict_mode#Syntax_errors

* https://developer.mozilla.org/en-US/Firefox/Releases/34#JavaScript

Any reviews to the wiki pages are very much appreciated.

Comment 11

[Tooru Fujisawa [:arai]]

Updated following document, which was pointed out by bug 1170752:
  https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Strict_mode

Comment 12

[sjkenny69]

[Tracking Requested - why for this release]: