misc: add trigram index on unaccented role names (#87906)

src/authentic2/a2_rbac/migrations/0040_role_name_idx.py

@@ -0,0 +1,29 @@
+# Generated by Django 3.2.23 on 2024-03-28 16:50
+
+import django.contrib.postgres.indexes
+import django.db.models.expressions
+import django.db.models.functions.text
+from django.db import migrations
+
+
+class Migration(migrations.Migration):
+    dependencies = [
+        ('a2_rbac', '0039_set_user_view_permissions_by_ou'),
+    ]
+
+    operations = [
+        migrations.AddIndex(
+            model_name='role',
+            index=django.contrib.postgres.indexes.GinIndex(
+                django.contrib.postgres.indexes.OpClass(
+                    django.db.models.functions.text.Upper(
+                        django.db.models.expressions.Func(
+                            django.db.models.expressions.F('name'), function='immutable_unaccent'
+                        )
+                    ),
+                    'public.gin_trgm_ops',
+                ),
+                name='name_idx',
+            ),
+        ),
+    ]

src/authentic2/a2_rbac/models.py

@@ -23,10 +23,12 @@ from django.conf import settings
 from django.contrib.auth import get_user_model
 from django.contrib.contenttypes.fields import GenericForeignKey, GenericRelation
 from django.contrib.contenttypes.models import ContentType
+from django.contrib.postgres import indexes as postgresql_indexes
 from django.contrib.postgres.fields import ArrayField
 from django.core.exceptions import ValidationError
 from django.core.validators import MinValueValidator
 from django.db import models
+from django.db.models.functions import Upper
 from django.db.models.query import Prefetch, Q
 from django.urls import reverse
 from django.utils.text import slugify
@@ -614,6 +616,14 @@ class Role(AbstractBase):
                 condition=models.Q(service__isnull=True, ou__isnull=True, admin_scope_ct__isnull=True),
             ),
         ]
+        indexes = [
+            postgresql_indexes.GinIndex(
+                postgresql_indexes.OpClass(
+                    Upper(models.Func(models.F('name'), function='immutable_unaccent')), 'public.gin_trgm_ops'
+                ),
+                name='name_idx',
+            ),
+        ]
 
     def natural_key(self):
         return [

src/authentic2/manager/forms.py

@@ -405,7 +405,7 @@ class ServiceRoleSearchForm(CssClass, PrefixFormMixin, FormWithRequest):
             for word in (w.strip() for w in self.cleaned_data.get('text').split(' ')):
                 if not word:
                     continue
-                qs = qs.filter(name__unaccent__icontains=word)
+                qs = qs.filter(name__immutable_unaccent__icontains=word)
         if not app_settings.SHOW_INTERNAL_ROLES and not self.cleaned_data.get('internals'):
             qs = qs.exclude(slug__startswith='_')
         return qs

src/authentic2/utils/lookups.py

@@ -1,4 +1,5 @@
 from django.contrib.postgres.lookups import Unaccent as PGUnaccent
+from django.db.models import CharField, TextField, Transform
 from django.db.models.functions import Concat
 from django.db.models.functions import ConcatPair as DjConcatPair
 
@@ -7,6 +8,16 @@ class Unaccent(PGUnaccent):
     function = 'immutable_unaccent'
 
 
+class UnaccentTransform(Transform):
+    bilateral = True
+    lookup_name = 'immutable_unaccent'
+    function = 'immutable_unaccent'
+
+
+CharField.register_lookup(UnaccentTransform)
+TextField.register_lookup(UnaccentTransform)
+
+
 class ConcatPair(DjConcatPair):
     """Django ConcatPair does not implement as_postgresql, using CONCAT as a default.