303261 - Javscript's Date.getUTCDay() function returns bad day number in British Summer Time

Status: RESOLVED INCOMPLETE

(Core :: JavaScript Engine, defect)

Description

[Bill Giel]

User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.7.10) Gecko/20050716 Firefox/1.0.6
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.7.10) Gecko/20050716 Firefox/1.0.6

This is an apparent universal bug in Javascript, and I get the same result in
IE. In order to see the bug, set the PC timezone to
Dublin,Edinburg,Lisbon,London and enable automatic daylight saving time
adjustment. Then visit the web page above to see the problem. Between March 27
and 28, the day number becomes incorrect, and will continue this way until a
date in October, when it will become correct. This bug is not apparent in US
timezones.

Reproducible: Always

Steps to Reproduce:
1.Set PC Timezone to Dublin,Edinburg, Lisbon, London and enable automatic
Daylight time adjustment
2. Browse http://www.rvdi.com/js-datebug.html
3. You should see the inconsistency of the functions output

Actual Results:  
The day number is incorrect starting with Mar 28 in BST timezone

Expected Results:  
Should have provided the correct day number (duh.)

Comment 1

[Steve England [:stevee]]

Attachment: testcase from reporter's URL

Comment 2

[Steve England [:stevee]]

Bill, can you try with Deer Park Alpha 2 (Firefox 1.5 alpha) and see if you
still see this bug? It may well have been fixed by now.

Comment 3

[Steve England [:stevee]]

No feedback from reporter, resolving INCOMPLETE. Reporter, if you still see this problem with a trunk build, please reopen!