sorting bugfix

Author: CosmoV

fastapi_jsonapi/common.py

@@ -3,12 +3,13 @@
 # noinspection PyProtectedMember
 from pydantic.fields import FieldInfo
 
-from fastapi_jsonapi.types_metadata import ClientCanSetId, CustomFilterSQL, RelationshipInfo
+from fastapi_jsonapi.types_metadata import ClientCanSetId, CustomFilterSQL, CustomSortSQL, RelationshipInfo
 from fastapi_jsonapi.utils.metadata_instance_search import MetadataInstanceSearch
 
 search_client_can_set_id = MetadataInstanceSearch[ClientCanSetId](ClientCanSetId)
 search_relationship_info = MetadataInstanceSearch[RelationshipInfo](RelationshipInfo)
 search_custom_filter_sql = MetadataInstanceSearch[CustomFilterSQL](CustomFilterSQL)
+search_custom_sort_sql = MetadataInstanceSearch[CustomSortSQL](CustomSortSQL)
 
 
 def get_relationship_info_from_field_metadata(

fastapi_jsonapi/data_layers/sqla/query_building.py

@@ -16,7 +16,7 @@
 from sqlalchemy.orm.util import AliasedClass
 from sqlalchemy.sql.elements import BinaryExpression
 
-from fastapi_jsonapi.common import search_custom_filter_sql
+from fastapi_jsonapi.common import search_custom_filter_sql, search_custom_sort_sql
 from fastapi_jsonapi.data_typing import TypeModel, TypeSchema
 from fastapi_jsonapi.exceptions import InvalidField, InvalidFilters, InvalidType
 from fastapi_jsonapi.exceptions.json_api import HTTPException
@@ -429,11 +429,7 @@ def build_sort_expressions(
             schema = relationships_info[relationship_path].target_schema
 
         schema_field = schema.model_fields[field_name]
-        custom_sort_sql: Optional[CustomSortSQL] = None
-        for sort_sql in search_custom_filter_sql.iterate(field=schema_field):
-            if sort_sql.op == sort_sql:
-                custom_sort_sql = sort_sql
-                break
+        custom_sort_sql: Optional[CustomSortSQL] = search_custom_sort_sql.first(field=schema_field)
 
         join_column = getattr(model, field_name)
         if custom_sort_sql is not None: