2024-08-07            CALCUTTA IS LOCATED IN DEBIAN TZDATA-LEGACY





For those running Debian and derivatives: is Emacs' worldclock showing
Bangalore ASIA instead of IST? One option: apt install tzdata-legacy.

In Emacs:

,----
| M-x world-clock
`----

should show something like:

,----
| Seattle   Wednesday 07 August 11:54 PDT
| New York  Wednesday 07 August 14:54 EDT
| London    Wednesday 07 August 19:54 BST
| Paris     Wednesday 07 August 20:54 CEST
| Bangalore Thursday 08 August 00:24 IST
| Tokyo     Thursday 08 August 03:54 JSTT
`----

If any of the answers is off, like this:

,----
| Bangalore Wednesday 07 August 18:54 ASIA
`----

then might you want to install tzdata-legacy[1]. Maybe.

Context
=========

At the beginning of 2024, Debian revised tzdata. From the
/usr/share/doc/tzdata/NEWS.Debian.gz:

 [...] the tzdata package ships only timezones that follow the
 current rules of geographical region (continent or ocean) and city
 name. All legacy timezone symlinks (old or merged timezones
 mentioned in the upstream backward file) were moved to
 tzdata-legacy. [...]

In other words, in Debian Testing and Unstable, tzdata no longer lists:

 ,----
 | /usr/share/zoneinfo/Asia/Calcutta
 `----

It does list:

 ,----
 | /usr/share/zoneinfo/Asia/Kolkata
 `----

Calcutta and other legacy placenames are now in tzdata-legacy.

Choices!
==========

The other option would be to modify the:

 ,----
 | world-clock-list
 `----

to use Kolkata, after all the city's name since 2001, Wikipedia[2] shows.

 ,----
 | ("Asia/Kolkata" "Bangalore")
 `----

Like this:

 ,----
 | (setopt world-clock-list '(("America/Los_Angeles" "Seattle")
 |                            ("America/New_York" "New York")
 |                            ("Europe/London" "London")
 |                            ("Europe/Paris" "Paris")
 |                            ("Asia/Kolkata" "Bangalore")
 |                            ("Asia/Tokyo" "Tokyo")))
 `----

I asked about this on the emacs-devel mailing list. The maintainers
have already made this change to Emacs master, writing:

“It's safe to change time.el to use Asia/Kolkata now, as the standard
name changed in 2008 and even ancient systems keep up with TZDB in
order to function properly.”

[1]: https://packages.debian.org/search?suite=default&section=all&arch=any&searchon=names&keywords=tzdata-legacy

[2]: https://en.wikipedia.org/wiki/Kolkata