Add unaccent to SearchFilter

[mgaligniana]

Description

Based on discussion #7759 I've created this PR to continue the work made in #8775 and #7733

There are no tests with PostgreSQL but I'm creating this to test with the CI

[mgaligniana]

Hi @auvipy!

In case I would like to add a postgres db creation step, to be able to add new tests: should I add a step here .github/workflows/main.yml?

[mgaligniana]

I move this PR to Ready for review as the work is done but I need confirmation on how to add (or if it worth it) a step using PostgreSQL to be able to test it.

Thank you!

[jensjeflensje]

Tried this locally and the unaccent works great. It got me thinking though: anyone using unaccent is probably not interested in a full match either? The current code limits icontains from being used too alongside unaccent. I personally set my lookup prefix to "&": "unaccent__icontains" as that better fits my (and probably also other people's) usecases.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[Copilot]

Pull Request Overview

This PR adds unaccent support to the SearchFilter, enabling accent‐insensitive searches on PostgreSQL by mapping the "&" prefix to the "unaccent" lookup.

• Updates the lookup prefixes in the SearchFilter backend
• Introduces a PostgreSQL‑specific test for unaccent search
• Updates the API documentation to include the new lookup operator

Reviewed Changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
tests/test_filters.py	Added a new test class that verifies unaccent search functionality
rest_framework/filters.py	Updated lookup prefixes to include the unaccent operator
docs/api-guide/filtering.md	Added new documentation row for accent‑insensitive unaccent search lookup

[auvipy]

test is failing with following error

raise FieldError(
E django.core.exceptions.FieldError: Unsupported lookup 'unaccent' for CharField or join on the field not permitted.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[mgaligniana]

test is failing with following error

raise FieldError( E django.core.exceptions.FieldError: Unsupported lookup 'unaccent' for CharField or join on the field not permitted.

Yes!

But is because the test is not being run over a PostgreSQL database, right?

I've tried adding this @pytest.mark.skipif(not postgres_fields, reason='PostgreSQL support (postgres_fields) is not available') to see if it is skiped by the CI, but nope! Any suggesiton?

[mgaligniana]

I've noticed that @ search never had a test with @ filter.

How bad it would be add this without testing? (as it is the same case)

[mgaligniana]

Hi @browniebroke! Just wondering if my last comment makes sense, or if you have any suggestions. Thank you!

[browniebroke]

I've noticed that @ search never had a test with @ filter.

Yes precisely. We've got some blind spots in our test coverage and we're trying to cover these kind of missing cases