Deprecate CICharField, CIEmailField, CITextField

[Mariusz Felisiak]

Hi y'all,

    Django 3.2+ supports "db_collation" [1] for "CharField" and "TextField" along with migration operations ("CreateCollation()", "RemoveCollation") and the database function "Collate()" [3]. Moreover CI fields and the entire "citext" module are discouraged since PostgreSQL 12 [4] in favor of collations. I think it's time to deprecate CI fields from the "contrib.postgres" in favor of "CharField" and "TextField" with case insensitive collations (and remove them in Django 5.0).

Best,
Mariusz

[1] https://code.djangoproject.com/ticket/31777
[2] https://code.djangoproject.com/ticket/32046
[3] https://code.djangoproject.com/ticket/21181
[4] https://www.postgresql.org/docs/12/citext.html

[Adam Johnson]

My initial concern was around the minimum PostgreSQL version that Django 5.0 will support. According to https://en.wikipedia.org/wiki/PostgreSQL#Release_history , PostgreSQL 10 is supported until 2022-11-10 , and version 11 until 2023-11-09. With Django 5.0 expected in 2024-01, it should be fine to deprecate the CI fields for removal in Django 5.0. Users on old PostgreSQL versions can manage the deprecation warning until they upgrade.

So +1 from me.

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[Paolo Melchiorre]

Hi Mariusz,

I agree with you on deprecating and then removing CI fields.

I only would suggest adding some examples of migrations from CI fields
to collations in the deprecation notes to help users to easily
migrate.

So +1 for me too.

Ciao,
Paolo

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[Tom Carrick]

Hi,

I'm not too sure about this.

While Postgres encourages using non-deterministic collations, they're not without their downsides. For example, you can't do a LIKE query on a field using a non-deterministic collation, but you can with CItext - although I don't believe there's a way to index it. Say, for example, you want to store your user emails CI - this is great for logging in but it makes it impossible to search for users with a particular email domain, or trying to find someone by the username part, say.

On the other hand, we could just say: don't use either, put an index on UPPER and make sure you always use iexact.

I don't have a very strong opinion.

Cheers,

Tom

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[Mariusz Felisiak]

wtorek, 25 stycznia 2022 o 13:59:54 UTC+1 Adam Johnson napisał(a):

My initial concern was around the minimum PostgreSQL version that Django 5.0 will support. According to https://en.wikipedia.org/wiki/PostgreSQL#Release_history , PostgreSQL 10 is supported until 2022-11-10 , and version 11 until 2023-11-09. With Django 5.0 expected in 2024-01, it should be fine to deprecate the CI fields for removal in Django 5.0. Users on old PostgreSQL versions can manage the deprecation warning until they upgrade.

Yes, support for PostgreSQL 10 will be dropped in Django 4.2, and support for PostgreSQL 11 will be dropped in Django 5.0.

 

[Mariusz Felisiak]

> Support for PostgreSQL 10 was dropped in Django 4.1, and support for PostgreSQL 11 was dropped in Django 4.2.

When CICharField, CIEmailField, CITextField deprecation starts in Django 4.2 they will be removed in Django 5.1.

[Mariusz Felisiak]

https://code.djangoproject.com/ticket/33872

[Silvio]

Since these are PotsgreSQL-specific fields that are being deprecated, might it make sense to provide a hint as to what the CreateCollation() call should be?

I'm looking around and it's not immediately obvious. The CreateCollation() examples in Django are for a German phone book, where in reality, I think 99% of cases are going to be for case insensitive emails.

The deprecation notice in the patch currently shows an ellipsis.

On Thursday, July 28, 2022 at 7:03:10 AM UTC-4 Mariusz Felisiak wrote:

https://code.djangoproject.com/ticket/33872

[Mariusz Felisiak]

As far as I'm aware you can use:

     CreateCollation("case_insensitive", "und-u-ks-level2", provider="icu", deterministic=False)

to create a case insensitive collation on PostgreSQL.