Fix Unicode product search

backend/api/v1/commerce/viewsets.py

@@ -29,6 +29,7 @@ from commerce.services import (
 )
 from commerce.services.credentials import CredentialError
 from commerce.integrations.moysklad import MoySkladError
+from commerce.search import UnicodeCasefoldSearchFilter
 from commerce.tasks import enqueue_connection_sync
 
 from .permissions import CommerceAccessPermission
@@ -190,11 +191,16 @@ class ProductViewSet(viewsets.ModelViewSet):
     permission_classes = [CommerceAccessPermission]
     filter_backends = [
         DjangoFilterBackend,
-        filters.SearchFilter,
+        UnicodeCasefoldSearchFilter,
         filters.OrderingFilter,
     ]
     filterset_fields = ["kind", "is_active", "parent"]
-    search_fields = ["sku", "name", "barcode", "bindings__external_sku"]
+    search_fields = [
+        "sku__unicode_casefold__contains",
+        "name__unicode_casefold__contains",
+        "barcode__unicode_casefold__contains",
+        "bindings__external_sku__unicode_casefold__contains",
+    ]
     ordering_fields = ["sku", "name", "created_at", "updated_at"]
     ordering = ["name", "sku"]
 

backend/commerce/apps.py

@@ -7,4 +7,5 @@ class CommerceConfig(AppConfig):
     verbose_name = "Товарная аналитика"
 
     def ready(self):
+        from . import search  # noqa: F401
         from . import signals  # noqa: F401

backend/commerce/search.py

@@ -0,0 +1,47 @@
+from django.db.backends.signals import connection_created
+from django.db.models import CharField, Transform
+from django.dispatch import receiver
+from rest_framework.filters import SearchFilter
+
+
+SQLITE_CASEFOLD_FUNCTION = "EUSRR_CASEFOLD"
+
+
+def _casefold(value):
+    return None if value is None else str(value).casefold()
+
+
+@receiver(connection_created, dispatch_uid="commerce.sqlite_unicode_casefold")
+def register_sqlite_casefold(sender, connection, **kwargs):
+    if connection.vendor != "sqlite":
+        return
+    connection.connection.create_function(
+        SQLITE_CASEFOLD_FUNCTION,
+        1,
+        _casefold,
+        deterministic=True,
+    )
+
+
+class UnicodeCasefold(Transform):
+    lookup_name = "unicode_casefold"
+    function = "LOWER"
+    output_field = CharField()
+
+    def as_sqlite(self, compiler, connection, **extra_context):
+        return super().as_sql(
+            compiler,
+            connection,
+            function=SQLITE_CASEFOLD_FUNCTION,
+            **extra_context,
+        )
+
+
+CharField.register_lookup(UnicodeCasefold)
+
+
+class UnicodeCasefoldSearchFilter(SearchFilter):
+    """DRF substring search with Unicode-aware case normalization."""
+
+    def get_search_terms(self, request):
+        return [term.casefold() for term in super().get_search_terms(request)]

backend/tests/commerce/test_api.py

@@ -42,6 +42,22 @@ def test_employee_can_read_but_cannot_create_product(api_client, user_factory):
     assert create_response.status_code == status.HTTP_403_FORBIDDEN
 
 
+def test_product_search_matches_unicode_substring_without_case(api_client, user_factory):
+    user = user_factory()
+    Product.objects.create(sku="SEA-001", name="Автомат «Бродяги морей»")
+    Product.objects.create(sku="OTHER-001", name="Другой товар")
+    api_client.force_authenticate(user=user)
+
+    response = api_client.get(
+        reverse("api:v1:commerce:product-list"),
+        {"search": "бродяг"},
+    )
+
+    assert response.status_code == status.HTTP_200_OK
+    assert response.data["count"] == 1
+    assert response.data["results"][0]["name"] == "Автомат «Бродяги морей»"
+
+
 def test_staff_can_create_product(api_client, user_factory):
     user = user_factory(staff=True)
     api_client.force_authenticate(user=user)