600943 - Date.prototype.toJSON computes 'this' incorrectly

Status: RESOLVED FIXED

(Core :: JavaScript Engine, defect)

Description

[Jim Blandy :jimb]

Attachment: Correctly compute |this| in Date.prototype.toJSON.

ES5 15.9.5.44 step 1 says that Date.prototype.toJSON must apply ToObject to the given |this| value. However, jsdate.cpp:date_toJSON calls ComputeThisFromVp, which does null->global and other sorts of transitions.

With the strict |this| patch applied, this causes regressions in ecma_5/Date/toJSON-01.js (but only in the browser, as the real global and the XPCCrossOriginWrapper seem to respond to DefaultValue differently, leading the shell to spuriously throw the correct error).

Comment 1

[Jeff Walden [:Waldo]]

Comment on attachment 479882 [details] [diff] [review]
Correctly compute |this| in Date.prototype.toJSON.

I had completely forgotten about toJSON-01.js conditionally testing strict-this behavior!

Let's remove the if-strict-mode-this-is-supported guard around these tests since we know we support it now, same as with the function bind test changes.

Comment 2

[Jeff Walden [:Waldo]]

...in the strict-this bug, of course, after this patch lands as-is.

Comment 3

[Jim Blandy :jimb]

http://hg.mozilla.org/tracemonkey/rev/3bd3e00203fa

Comment 4

[Robert Sayre]

http://hg.mozilla.org/mozilla-central/rev/3bd3e00203fa