261887 - for..in statement vs. delete - ECMA compliance

Status: VERIFIED FIXED

(Core :: JavaScript Engine, defect, P4)

Description

[Oscar Fogelberg]

User-Agent:       Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; .NET CLR 1.1.4322)
Build Identifier: js-1.5-rc6a

I believe that SpiderMonkey has a problem in the for-in implementation.

12.6.4 of ECMA-262 which defines the for-in Statement states that "If a 
property that has not yet been visited during enumeration is deleted, then it 
will not be visited"

We do not abide by this but rather SM visit properties that have been deleted 
prior to them being visited and finds them being undefined.

Reproducible: Always
Steps to Reproduce:
//Run the following script:

count = 0;
result = "";
value = "";

t = new Object();
t.one = "one";
t.two = "two";
t.three = "three";
t.four = "four";
    
for (var prop in t) {
   if (count==1) delete(t.three);
   count++;
   value = value + t[prop];
   result = result + prop;
}

Actual Results:  
value == onetwoundefinedfour
result == onetwothreefour


Expected Results:  
value == onetwofour
result == onetwofour

Comment 1

[Brendan Eich [:brendan]]

Taking, also giving Oscar canconfirm privs.

/be

Comment 2

[Brendan Eich [:brendan]]

Attachment: proposed fix

Easy.

/be

Comment 3

[Mike Shaver (:shaver -- probably not reading bugmail closely)]

Comment on attachment 160432 [details] [diff] [review]
proposed fix

Another for the test pile! r=shaver

Comment 4

[Brendan Eich [:brendan]]

Fixed on trunk.  Proposing for branches -- another safe ECMA conformance fix.

/be

Comment 5

[Asa Dotzler [:asa]]

Comment on attachment 160432 [details] [diff] [review]
proposed fix

a=asa for checkin to the aviary and 1.7 branches.

Comment 6

[Asa Dotzler [:asa]]

p4 priority - not a blocker. patch approved to land.

Comment 7

[Brendan Eich [:brendan]]

Fixed on the branches.

/be

Comment 8

[Bob Clary [:bc] (inactive)]

Attachment: js1_5/Regress/regress-261887.js

Oscar, with your permission this will be included in the javascript test
library.

Comment 9

[Oscar Fogelberg]

Permission Granted, Thanks!
/Oscar

Comment 10

[Bob Clary [:bc] (inactive)]

js/tests/js1_5/Regress/regress-261887.js checked in. Thanks Oscar!

Comment 11

[Bob Clary [:bc] (inactive)]

verified fixed.