#1827 - Calendar events with an advanced recurrence pattern do not display properly after DST changes
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By PDStig
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| Identifier | #1827 |
|---|---|
| Issue type | Trivial issue (does not break functionality) |
| Title | Calendar events with an advanced recurrence pattern do not display properly after DST changes |
| Status | Completed |
| Handling member | PDStig |
| Addon | calendar |
| Description | Calendar events that have an advanced recurrence (using the recurrence pattern of 1 and 0 option) do not display correctly in the calendar after a shift from standard to daylight savings time. |
| Steps to reproduce | 1. Create an event in the standard time. 2. Give it a recurrence pattern. 3. Daylight Savings time. 4. Check the calendar. Sometimes it will display when it shouldn't (when using # days filter) and sometimes it will display on the wrong days. |
| Additional information | In the screenshot, the circled "Democracy Now" event has a start in November of 2014 (when Standard Time was in effect). The event is supposed to occur Monday-Friday. What you see is a block that shows Calendar events for 3 days. March 15th is a Sunday, and Democracy Now does not occur on a Sunday. In addition, Sunday is in the 4th day range, and I have the limit set to 3 days. There are other events on Sunday as well, but they correctly do not render yet as it is not time. |
| Funded? | No |
| Commits |
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Comments
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There is a bug in the DST shift calculations regarding events that can cause day shifting inadvertently.
It's really confusing because there are MULTIPLE DST shifts. So for example, a New York event may be 5pm UTC at start of March, 4pm UTC mid-way through March (as event's timezone's DST shifted) -- while in New York it stays at 1pm -- while in say London it is 5pm at start of March, 4pm mid-way through March, then back to 5pm in April (because the latter London DST kicked in, to pair up with the earlier New York DST).
Trying to trace timestamps through all the correct conversions when all these little shifts are happening is more than human working memory can hold ;-).