254296 - javascript regular expression negative lookahead

Status: VERIFIED FIXED

(Core :: JavaScript Engine, defect)

Description

[Michael Ash]

User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.7) Gecko/20040626 Firefox/0.9.1
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.7) Gecko/20040626 Firefox/0.9.1

Using client-side javascript regular expression a negative lookahead (?!) the
look-ahead fails before the entire group is evaluated.  Seem to short-curciut
For example ^\d(?!\.\d)  ,a digit not followed by a decimal and a digit,fails to
match 3.A because it the digit is followed by a decimal.  Doesn't check to see
if the decimal was followed by a digit.  The same expression tested using IE and
Opera matched 3.A 
Used the webpage http://www.unusualresearch.com/regex/toolrei.htm to test with.

Reproducible: Always
Steps to Reproduce:
1.Used the webpage http://www.unusualresearch.com/regex/toolrei.htm or
http://www.regexlib.com/RETester.aspx with javascript option using Mozilla or
Firefox
2. use regular expression  ^\d(?!\.\d)
3.Test with string 3.A

Actual Results:  
No match was found

Expected Results:  
Found 1 match

Comment 1

[Brendan Eich [:brendan]]

Sweet, sweet regexp, as shaver would say.  Rogerl's big rewrite regained the
long-lost Netscape 4.x-era bytecoded NFA performance, but here's yet another bug
as fallout, or payback.

/be

Comment 2

[Brendan Eich [:brendan]]

Attachment: proposed fix

Both REOP_ASSERT and REOP_ASSERT_NOT assumed that a leading "simple" reop was
all there was in the assertion, failing to see whether SimpleMatch advanced pc
to the next pc after the assertion.

Comment 3

[Mike Shaver (:shaver emeritus)]

Comment on attachment 155753 [details] [diff] [review]
proposed fix

I wonder how many more licks we need to get to the centre. r=shaver.

Comment 4

[Brendan Eich [:brendan]]

Comment on attachment 155753 [details] [diff] [review]
proposed fix

Should get into all active branches ASAP.

/be

Comment 5

[Brendan Eich [:brendan]]

Fixed on the trunk.

/be

Comment 6

[Daniel Veditz [:dveditz]]

Comment on attachment 155753 [details] [diff] [review]
proposed fix

a=dveditz for 1.7.3

Comment 7

[Ben Goodger (use ben at mozilla dot org for email)]

Comment on attachment 155753 [details] [diff] [review]
proposed fix

a=[e-mail]

Comment 8

[Brendan Eich [:brendan]]

Fixed on MOZILLA_1_7_BRANCH and AVIARY_1_0_20040515_BRANCH.

/be

Comment 9

[Bob Clary [:bc] (inactive)]

Attachment: js1_5/Regress/regress-254296.js

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

Comment 10

[Michael Ash]

(In reply to comment #9)
> Created an attachment (id=174927) [edit]
> js1_5/Regress/regress-254296.js
> 
> Michael, with your permission this will be included in the javascript test
> library.

Sure.  Glad I could help

Comment 11

[Bob Clary [:bc] (inactive)]

js/testsjs1_5/Regress/regress-254296.js checked in. Thanks Michael!

Comment 12

[Bob Clary [:bc] (inactive)]

verified fixed.