350712 - Iteration in catchguard causes "undefined" exception

Status: RESOLVED WORKSFORME

(Core :: JavaScript Engine, defect)

Description

[Jesse Ruderman]

function ii() { for (var i in []); } 

try { 
  try{
    throw 5;
  } catch(ex if ii()) {
  }
} catch(er) { 
  alert(er) 
}

Result: alert saying "undefined".

Expected: no alert.

Comment 1

[Tom S]

This is not an bug, as ii always returns undefined, which is coerces to false. So the the error won't be caught and propagated to the outer try..catch block.

Comment 2

[Tom S]

Oh but the error "undefined" is indeed a bug, which has been fixed. We now get '5';

Comment 3

[Tom S]

Test: http://hg.mozilla.org/tracemonkey/rev/9a8651caaa0a