56868 - Error objects have wrong [[Class]] property

Status: VERIFIED FIXED

(Core :: JavaScript Engine, defect, P3)

Description

[David Flanagan]

All NativeError objects, including Error, TypeError, etc. have
the wrong [[Class]] property.  ECMA3 says it should be "Error"
But in js15rc1, Object.prototype.toString() reports it as "Exception".

Comment 1

[David Flanagan]

I forgot to cite what portions of the spec I'm referring to.

See 15.11.1.1 and 15.11.7.2

Comment 2

[Phil Schwartau]

From ECMA3 document -


15.11.1.1 Error (message)

The [[Prototype]] property of the newly constructed object is set to the original 
Error prototype object, the one that is the initial value of Error.prototype 
(section 15.11.3.1).

The [[Class]] property of the newly constructed object is set to "Error".
If the argument message is not undefined, the message property of the newly 
constructed object is set to ToString(message).



15.11.7.2 NativeError (message)

The [[Prototype]] property of the newly constructed object is set to the 
prototype object for this error constructor.

The [[Class]] property of the newly constructed object is set to "Error".
If the argument message is not undefined, the message property of the newly 
constructed object is set to ToString(message).

Comment 3

[Brendan Eich [:brendan]]

Roger may have missed this because it was UNCONFIRMED.  It's real.  Please fix 
for js1.5 (with a patch attached, reviewed, and in the trunk, we can make a last 
minute attempt for Netscape 6 rtm).

/be

Comment 4

[rogerl (gone)]

Attachment: Change "Exception" to "Error" in class defn.

Comment 5

[Mike McCabe]

r=mccabe.  Looks like we're OK in rhino.

Comment 6

[rogerl (gone)]

just need an sr= on the patch, it's trivial.

Comment 7

[Patrick C. Beard]

Marking 0.8.1, let's get some reviews quick!

Comment 8

[Brendan Eich [:brendan]]

Any such clearly conforming class name change in the future gets an automatic
sr=[e-mail] pre-approval.

/be

Comment 9

[rogerl (gone)]

Fix checked in.

Comment 10

[Phil Schwartau]

Testcases added to JS test suite: 

                   js/tests/ecma_3/Object/class-003.js
                   js/tests/ecma_3/Object/class-004.js


These check the [[Class]] property of all the NativeError objects,
where we expect [[Class]] = "Error"; and the NativeError constructors, 
where we expect [[Class]] = "Function". Both tests pass in the current 
debug and optimized JS shells on WinNT and Linux.


Marking bug VERIFIED FIXED.