WIP: initial poc of switching to holidays python library by eyJhb · Pull Request #829 · thunderbird/thunderbird-website

eyJhb · 2025-05-23T20:49:05Z

This is just an initial POC of how it could look like, if we switched to the Holidays library in Python. It works fairly well, and it seems to be well maintained, with an active userbase.

The library in question https://github.com/vacanza/holidays

This PR needs a lot of cleanup. I just threw it together, to get some idea of how everything works together. But this should be fairly doable? However, the calendar will look vastly different from the old one, and there are a lot more types in this calendar (bank, government, school, etc. etc.).

This would close #753 , if it gets implemented fully.

TODO:

Update holiday-calendar.md to reflect how to run this code
- Ensure holidays is UPDATED (pip)
- How to contribute/fix data
Sanity check if this is good enough?
No need to require the API key if using this new provider

Any maintainer of this project are 100% welcome to take the steps I've made, and build upon it so it can be pushed and start getting used :)

janbrasna

FYI I did generate the actual .ics too, janbrasna@fe68215 — in case we want to show folks the new data and check how viable it is for their regions…

One thing to add to TODO: no need to require the API key if using this new provider.

One nit spotted:

janbrasna · 2025-05-28T17:23:41Z

 python-dateutil~=2.8.2
 packaging~=23.1
 setuptools==78.1.1
+hollidays>=0.73


That doesn't seem right, probably:

Suggested change

hollidays>=0.73

holidays>=0.73

eyJhb · 2025-05-29T22:39:56Z

i've tried to clean up the code a bit (not pushed yet), but most of it ended up in the model instead. I still think it looks cleaner in the end, but I'll remove a bunch of more stuff.

I'll try to get it pushed tomorrow at some point :) It shouldn't change the output, EXCEPT that I'm now skipping any calendars with NO events. Otherwise we would produce empty calendars that would error out the parser AFAIK. But this should maybe be changed :)

eyJhb · 2025-05-30T13:29:59Z

I've pushed the changes now, and there are quite some. I also tried to update the holidays-calendars.md file a bit, or at least remove calendarific references.

I've moved most of the logic into the VacanzaHoliday model instead, to make it more simple and clear. It's not really that pretty, any of the code, but it's hopefully not impossible to read.

I've tried to not touch too much of the Calendar things, e.g. from_api.

MelissaAutumn · 2025-05-30T16:52:21Z

Hello! Apologies I've been busy on other projects. Will hopefully get to this review by EOD today (my time) or early next week.

Thanks again!

eyJhb · 2025-05-30T17:50:54Z

Hello! Apologies I've been busy on other projects. Will hopefully get to this review by EOD today (my time) or early next week.

Thanks again!

No worries, take your time! :) Thus far I'm really impressed with the engagement from the team. That's always nice to see :)
Let me know if there is anything else I can do, and do not be afraid to ping me, I don't mind :)

eyJhb · 2025-06-26T17:15:42Z

Throwing in a tiny bump here :)

janbrasna

This is looking really good — I've generated the calendars a few times as the library updates progressed, and shared with people who were concerned with their locale caldata quality to evaluate. And the TLDR is: anything is better than the current state;D

janbrasna · 2025-10-25T19:19:35Z

 python-dateutil~=2.8.2
 packaging~=23.1
 setuptools==78.1.1
+holidays>=0.73


Let's bump to:

Suggested change

holidays>=0.73

holidays>=0.83

that has all the required regions we need.

janbrasna · 2025-10-27T15:34:19Z

This PR has currently a conflict with master that needs rebasing, but hopefully it's just some easy readme or config.

While I think removing the old model and provider is called for, as there's not really a reason to go back, there are tests relying on some of its specifics. If this approach is (pre-)approved by the maintainers, the tests would also need updating for the new data.

janbrasna · 2025-10-27T15:38:23Z

QQ: … and I've also seen it in tests — is it expected to have the holidays sets as OPAQUE i.e. as "busy" by default? Or that's a feature, for the public/national/bank holidays per se? (And in case there would be other types of holiday events added/configured like observance or religious, those would conversely be configured as TRANSPARENT explicitly for the difference?)

MelissaAutumn

Looking good, I see calendar events and afaik they look correct...besides some French where it doesn't belong 😄 If you have some time and are still willing to work on this, could you rebase and update tests as well?

Apologies for the long delay, we've been quite busy over here!

MelissaAutumn · 2025-05-26T17:21:43Z

+        subdivs = cal.subdivisions
+
+        # get the names for all the subdivisions
+        subdiv_to_name = {v: k for k, v in cal.subdivisions_aliases.items()}


I think you can probably drop retrieving the aliases.

It doesn't look like we could reverse this dict as at least in Canada aliases include the French names for Provinces but no information on what locale the name might be from. (https://holidays.readthedocs.io/en/latest/auto_gen_docs/canada/#holidays.countries.canada.Canada.subdivisions)

MelissaAutumn · 2025-05-26T17:30:27Z

+                subdiv=subdiv,
+                categories=cal.supported_categories,
+            )
+            for d, n in tcal.items():


nit: I think we can write out date and name, it's only a few more letters 😄

MelissaAutumn · 2025-05-26T18:02:15Z

+        # this should really be localised, but uncertain how to do this best
+        subdivs_except_text = ""
+        if subdivs_except:
+            subdivs_except_text = "All except "


I think this would be okay to localize ourselves, so you can probably pull in gettext_object from translate.py and pass in the locale. It should return an initialized gettext instance so you can use the return value like:

regions = ', '.join(subdivs) translator.gettext('All except %(list_of_regions)s' % {'list_of_regions': regions}) Which might produce: All Except BC, ON, QC

Unfortunately we use old-style python string formats for l10n. The localizers will see this as just All except %(list_of_regions)s so they can place it as needed.

MelissaAutumn · 2025-10-27T16:04:26Z

-```
-
-If you are an MZLA employee you can find the api key within the infra vault in 1password.
+Please ensure that you are using the latest release of the hollidays library.


Suggested change

Please ensure that you are using the latest release of the hollidays library.

Please ensure that you are using the latest release of the holidays library.

MelissaAutumn · 2025-10-27T16:20:07Z

+                categories=cal.supported_categories,
+            )
+
+            map_subdiv_to_name = {v: k for k, v in cal.subdivisions_aliases.items()}


This doesn't seem to work for Canadian holidays, as our aliases include the french name for it as well. However not all provinces have an official french name like Manitoba.

('British Columbia', 'BC'), ('Colombie-Britannique', 'BC')

leading to the BC => Colombie-Britannique overriding the english name

which ends up with SUMMARY:British Columbia Day (Colombie-Britannique).

I'm not sure if there's a good fix here, might be an issue we would need to raise with the library.

MelissaAutumn · 2025-10-27T16:23:07Z

^ I forgot I had half a review ready from May 🤦

janbrasna · 2025-10-29T20:37:48Z

+            # insert the excluded text here
+            # it should be done in a better way than this...
+            excluded_text = "All except "


Ah, I was surprised where the "Año Nuevo Judío (Rosh Hashana) (All except Tucumán)" comes from in those instances;)

QQ: If that is wrapped in gettext… does the calendar generation actually run in any l10n context, to apply anything besides just the en-US defaults for such strings?

EDIT: Now I see the comment above, where Mel describes how to add an initialized instance — nice!

initial poc of switching to vacanza holidays python library

ca4e134

eyJhb marked this pull request as draft May 23, 2025 20:49

pretty much done, should have some featureset as previous implementation

b192d45

janbrasna reviewed May 28, 2025

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eyJhb added 6 commits May 30, 2025 15:15

remove calendarific api key requirement

d456bbc

removed some of the calendarific components

e9494da

fixed requirements file

13268f1

changed how holidays provider works

fdaf877

updated markdown documentation

b2a7a87

more to holidays-calendars.md

f5a93ec

This was referenced Oct 23, 2025

media/caldata/SwedishHolidays.ics: Restore public holidays, remove non-public observances, and add Swedish names for all observances #941

Open

use free software to generate public calendars #753

Open

janbrasna reviewed Oct 27, 2025

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MelissaAutumn requested changes Oct 27, 2025

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janbrasna reviewed Oct 29, 2025

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janbrasna mentioned this pull request Nov 17, 2025

Translate or make “National Holiday” (and all other prefixes) translatable for end users of calendars around the world #972

Open

	Please ensure that you are using the latest release of the hollidays library.
	Please ensure that you are using the latest release of the holidays library.

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eyJhb commented May 23, 2025 •

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