Recurring events that span DST shifts are displayed wrong in winter-time

Bug #306212 reported by Ronald van Engelen on 2008-12-08
This bug affects 1 person
Affects Status Importance Assigned to Milestone
Douglas Cerna

Bug Description

Recurring events which span the daylight savings shift in autumn and winter are displayed wrong. This renders the current use of schooltool as a school-wide calendar unusable.

For example, giving the following event:
 * Site-wide timezone: Europe/Amsterdam
 * Start (according to edit ui): october 1, 2008 - 09:00
 * Recurrence: weekly for one year

Regarding the start time of this event:
 * according to the schooltool edit ui it starts at 09:00
 * according to the ICS-file it starts at 07:00 UTC each thursday
 * according to all schooltool views it starts at 08:00 in wintertime and starts at 09:00 in summer time

We of course would like to meet each thursday at 09:00 in our local time, regardless of time of year.

This problems seems to be the same as described in http://<email address hidden>/msg00110.html

Changed in schooltool:
importance: Undecided → High
milestone: none → jaunty
description: updated
description: updated
Thom Hastings (tghastings) wrote :

I'm going to try, this will be my first bugfix ever.
Any help or mentorship will be appreciated.

Changed in schooltool:
assignee: nobody → tghastings
Thom Hastings (tghastings) wrote :

Doing some quick research, it looks like Zoneinfo ( could be helpful.

Changed in schooltool:
assignee: tghastings → ignas
Ignas Mikalajūnas (ignas) wrote :

This is because schooltool is storing event start time as a UTC date. So the preferred timezone is only used for date entry/date display at the moment.

It is fixable, but would take a lot of time, as some parts of the system are assuming a uniform date storage format and would have to be fixed as well.

Changed in schooltool:
milestone: jaunty → none
status: New → Confirmed
Tom Hoffman (tom-hoffman) wrote :

Does this happen with timetables and section meeting times as well? That would be a more serious bug.

Changed in schooltool:
importance: High → Medium
tags: added: known-bugs
Ronald van Engelen (ronalde) wrote :

I've tested this in a test environment (schooltool 2008.10 on jaunty); it doesn't happen with timetables.

tags: added: calendar
Changed in schooltool:
assignee: Ignas Mikalajūnas (ignas) → Justas Sadzevičius (justas-pov)
Changed in schooltool:
importance: Medium → High
Gerhard Schneider (gs-ilsb) wrote :

How to reproduce the bug:

European DST change was on Oct. 26th this year

Go to the calendar
Create an event on Oct. 23th 22:00-22:30
Repeat every week
Repeat 2 times

Events created: Oct. 23th 22:00-22:30
                          Oct. 30th 21:00-21:30

Changed in schooltool:
assignee: Justas Sadzevičius (justas-pov) → Douglas Cerna (replaceafill)
milestone: none → 2.7.0
Changed in schooltool:
milestone: 2.7.0 → 2.8.0
Changed in schooltool:
milestone: 2.8.2 → none

oh sweet jesus people how old is this bug?

On Wed, Dec 3, 2014 at 10:15 AM, Douglas Cerna <email address hidden>

> ** Changed in: schooltool
> Milestone: 2.8.2 => None
> --
> You received this bug notification because you are subscribed to the bug
> report.
> Title:
> Recurring events that span DST shifts are displayed wrong in winter-
> time
> To manage notifications about this bug go to:

Thom Hastings (tghastings) wrote 23 hours ago:

> oh sweet jesus people how old is this bug?

According to my calculations, today we should celebrate its 6th birthday.

That's one year younger than my daugther; I guess it's safe to say she has developed a bit more in her first 6 years ;)

Tom Hoffman (tom-hoffman) wrote :

To be honest, we're probably going to end up "fixing" all the time zone bugs by not letting you change the timezone from UTC. This crappy time zone implementation almost killed the entire project before it even got rolling.

To post a comment you must log in.
This report contains Public information  Edit
Everyone can see this information.

Other bug subscribers