PostGIS backend silently ignores most Index options when targeting a single GeometryField (expressions, condition, include, opclasses)

[Luciano de la Iglesia]

I have this model:

class Foo(models.Model):
    location = geomodels.PointField(geography=True, spatial_index=False)
    is_current = models.BooleanField()

    class Meta:
        indexes = [
            GistIndex(fields=["location"], condition=Q(is_current=True), name="current_foo"),
        ]

When I create the migration, the sql for my current_foo index is:

CREATE INDEX "current_foo" ON "webatds_foo" USING GIST ("location");

This ignores my condition, I expect it to be:

CREATE INDEX "current_foo" ON "webatds_foo" USING GIST ("location") where is_current=true;

I'm using django 5.2.7, psycopg 3.2.12, and PostGIS 17.3.5.

[Simon Charette]

Confirmed this is a bug in in django.contrib.gis.db.backends.postgist (I inferred you were using PostGIS given you use contrib.postgres.ArrayField).

The SchemaEditor._create_index_sql method delegates to ._create_spatial_index_sql to provide some defaults (e.g. opclasses) but fails to pass along kwargs such as condition, include, expressions, etc, when calling super().

​It seems broken in multiple ways.

[Simon Charette]

A workaround in the meantime could be to use expressions=[F("location")] instead of fields=["location"]. You might have to explicitly specify ​the proper opclasses though, that would be point_ops in your case.