bug#35746: Evolution calendar gets the timezone wrong

[Ben Sturmfels <ben@sturm.com.au>]

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Hi Ludo,

On Thu, 16 May 2019, Ludovic Courtès wrote:
> Ben Sturmfels <ben@sturm.com.au> skribis:
>
>> In Evolution though, all my calendar events show up in UTC time, so I
>> have appointments showing up at eg. 1am.
>>
>> When I go to Edit, Preferences, Calendar and Task, General, under
>> timezone it says:
>>
>> [x] Use system time (UTC)
>
> Could you figure out how Evolution determines what the current time zone
> is?
>
> Guix provides /etc/localtime, which is what libc functions use, but I’m
> guessing Evolution uses a custom framework, possibly involving a
> hard-to-believe network of D-Bus services.

One clue is that when I run `evolution` in a terminal it logs the
following error:

(evolution:4359): libecal-CRITICAL **: 17:22:46.073: e_cal_util_get_system_timezone: assertion 'location != NULL' failed

So my C troubleshooting skills are very rusty, but this is a learning
opportunity!

`strace evolution 2>&1 | grep /etc/localtime` indicates /etc/localtime
is being opened at least.

I've downloaded the source with `guix build --source
evolution-data-server`, extracted and found the the function
"e_cal_util_get_system_timezone()" at src/calendar/libecal/e-cal-util.c:1507
which calls down to "system_timezone_find()" in e-cal-system-timezone.c:522
where it looks up the timezone and compares it to a list of valid zones.

So I run `gdb evolution`, but don't seem to have the debugging symbols.
How does one get/build the debugging symbols? Can `guix build` help with
this?

Possibly completely unrelated, but noting that both icecat and chromium
do this - which is wrong:

> new Date().getTimezoneOffset()
0

Where node does this - which is correct:

> new Date().getTimezoneOffset()
-600

Cheers,
Ben

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