225550 - RegExp toSource/toString return an invalid empty RE

Status: VERIFIED FIXED

(Core :: JavaScript Engine, defect, P1)

Description

[Thomas Much]

User-Agent:       Mozilla/5.0 (Macintosh; U; PPC Mac OS X Mach-O; en-US; rv:1.6a) Gecko/20031029
Build Identifier: Mozilla/5.0 (Macintosh; U; PPC Mac OS X Mach-O; en-US; rv:1.6a) Gecko/20031029

If I create an empty regular expression object an call toString or toSource on
it, I get "//" as the result. This isn't a valid RE string, since it's the start
of a comment:

var re    = new RegExp     // create an empty RE
var reSrc = re.toString()  // gives "//"
var re2   = eval(reSrc)    // gives "undefined" instead of an empty RE object

We should better return "/(?:)/" in this special case, as mentioned in ECMA262-3
7.8.5.

Reproducible: Always

Steps to Reproduce:




Most browsers (Mozilla, IE, Opera, iCab) show this behaviour, but a change for
this special case probably won't break any compatibility (I'm considering this
fix for iCab, too).

Comment 1

[Phil Schwartau]

Confirming for consideration -

Comment 2

[Brendan Eich [:brendan]]

.

Comment 3

[Brendan Eich [:brendan]]

Attachment: proposed fix

Simple and direct.

/be

Comment 4

[Brendan Eich [:brendan]]

Checked in.

/be

Comment 5

[Bryan]

Hi,
Not happening in Mozilla/5.0 (Windows; U; Win98; en-US; rv:1.6b) Gecko/20031113
in windows.

Comment 6

[Brendan Eich [:brendan]]

Wellander3: what, do you think I have a time machine, and can go back to
yesterday and check in for the build dated 20031113?  Please.

/be

Comment 7

[Bryan]

Hi,
Sorry I am not asking you to go back to yesterday.