#36261: `icontains` lookup doesn't work with case insensitive collations
-------------------------------------+-------------------------------------
Reporter: Craig de Stigter | Owner: (none)
Type: Bug | Status: new
Component: Database layer | Version:
(models, ORM) |
Severity: Normal | Resolution:
Keywords: | Triage Stage:
| Unreviewed
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
-------------------------------------+-------------------------------------
Comment (by Simon Charette):
[https://www.depesz.com/2025/01/10/waiting-for-postgresql-18-support-like-
with-nondeterministic-collations/ Relevant article on the subject].
It appears that Postgres 18+ does support `LIKE` against nondeterministic
collations so that should be taken into consideration when taking a
decision here.
> It seems that icontains (and iexact etc) comparisons should use ILIKE,
which would work fine in this situation
Are you sure of that? It appears that `ILIKE` is explicitly pointed out as
not being implemented as
[https://git.postgresql.org/gitweb/?p=postgresql.git;a=commitdiff;h=85b7efa1cdd63c2fe2b70b725b8285743ee5787f
it's unclear whether or not it makes sense].
> I have looked through git and ticket history and can't find any
discussion of why it's implemented using LIKE instead.
Some context for you
- ticket:3575#comment:5
- ticket:32485
> Alternatively, using x LIKE y COLLATE "default" seems to avoid the
issue in this case, although someone who knows more about collations
should probably weigh in on what other side-effects that might have...
Not an expert but I think this might cause more harm than good as it
basically ignore the specified collation on the column?
--
Ticket URL: <https://code.djangoproject.com/ticket/36261#comment:1>
Django <https://code.djangoproject.com/>
The Web framework for perfectionists with deadlines.
--
You received this message because you are subscribed to the Google Groups
"Django updates" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to [email protected].
To view this discussion visit
https://groups.google.com/d/msgid/django-updates/01070195a1c6c285-f2a17148-4efb-47b5-8e66-008f3359d44e-000000%40eu-central-1.amazonses.com.
