616798 - string.test global will produce unpredictable result

Status: RESOLVED DUPLICATE of bug 98409

(Core :: XPCOM, defect)

Description

[Roel]

User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 6.0; nl; rv:1.9.2.12) Gecko/20101026 Firefox/3.6.12 ( .NET CLR 3.5.30729)
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 6.0; nl; rv:1.9.2.12) Gecko/20101026 Firefox/3.6.12 ( .NET CLR 3.5.30729)

You can reproduce this by a bookmarklet:

Error:
javascript:var url="Rsolution.be";var i=0; while(i<5){   alert((/[[a-zA-Z_0-9]*\.\/?]*/gi).test(url));  i++;}

Workaround:
Without the "global" switch(/g), the result is as predicted:
javascript:var url="Rsolution.be";var i=0; while(i<5){   alert((/[[a-zA-Z_0-9]*\.\/?]*/i).test(url));  i++;}

Reproducible: Always

Steps to Reproduce:
1. In firefox, put this in the address bar
2. javascript:var url="Rsolution.be";var i=0; while(i<5){   alert((/[[a-zA-Z_0-9]*\.\/?]*/gi).test(url));  i++;}
3. The result will switch from true to false
Actual Results:  
true false true false true

Expected Results:  
true true true true true

If more info is needed you can contact me @ [e-mail]

Comment 1

[Boris Zbarsky [:bzbarsky]]

The 1.9.2 behavior is what the ECMAScript 3rd edition spec called for.  This has since been changed in 5th edition, because it was widely agreed to be confusing (though quite predictable, if you read the spec).  ;)

Gecko 2.0 will have the 5th edition behavior.