feat: auto-include primary key in CrudFactory searchable_fields (#130)

docs/module/crud.md

@@ -212,6 +212,9 @@ Two search strategies are available, both compatible with [`offset_paginate`](..
 
 ### Full-text search
 
+!!! info "Added in `v2.2.1`"
+    The model's primary key is always included in `searchable_fields` automatically, so searching by ID works out of the box without any configuration. When no `searchable_fields` are declared, only the primary key is searched.
+
 Declare `searchable_fields` on the CRUD class. Relationship traversal is supported via tuples:
 
 ```python

src/fastapi_toolsets/crud/factory.py

@@ -1211,12 +1211,26 @@ def CrudFactory(
         )
         ```
     """
+    pk_key = model.__mapper__.primary_key[0].key
+    assert pk_key is not None
+    pk_col = getattr(model, pk_key)
+
+    if searchable_fields is None:
+        effective_searchable = [pk_col]
+    else:
+        existing_keys = {f.key for f in searchable_fields if not isinstance(f, tuple)}
+        effective_searchable = (
+            [pk_col, *searchable_fields]
+            if pk_key not in existing_keys
+            else list(searchable_fields)
+        )
+
     cls = type(
         f"Async{model.__name__}Crud",
         (AsyncCrud,),
         {
             "model": model,
-            "searchable_fields": searchable_fields,
+            "searchable_fields": effective_searchable,
             "facet_fields": facet_fields,
             "order_fields": order_fields,
             "m2m_fields": m2m_fields,

tests/test_crud_search.py

@@ -211,14 +211,17 @@ class TestPaginateSearch:
         assert result.data[0].username == "active_john"
 
     @pytest.mark.anyio
-    async def test_search_auto_detect_fields(self, db_session: AsyncSession):
+    async def test_search_explicit_fields(self, db_session: AsyncSession):
-        """Auto-detect searchable fields when not specified."""
+        """Search works when search_fields are passed per call."""
         await UserCrud.create(
             db_session, UserCreate(username="findme", email="other@test.com")
         )
 
         result = await UserCrud.offset_paginate(
-            db_session, search="findme", schema=UserRead
+            db_session,
+            search="findme",
+            search_fields=[User.username],
+            schema=UserRead,
         )
 
         assert isinstance(result.pagination, OffsetPagination)