Batch Mutations for creating, updating, and deleting #438 (#653)

docs/guide/mutations.md

@@ -184,3 +184,20 @@ class Mutation:
 
 schema = strawberry.Schema(mutation=Mutation)
 ```
+
+## Batching
+
+If you need to make multiple creates, updates, or deletes as part of one atomic mutation you can use batching. Batching has a similar syntax except that the mutations take and return a list.
+
+```python title="schema.py"
+import strawberry
+from strawberry_django import mutations
+
+@strawberry.type
+class Mutation:
+    createFruits: list[Fruit] = mutations.create(list[FruitPartialInput])
+    updateFruits: list[Fruit] = mutations.update(list[FruitPartialInput])
+    deleteFruits: list[Fruit] = mutations.delete(list[FruitPartialInput])
+
+schema = strawberry.Schema(mutation=Mutation)
+```

strawberry_django/mutations/fields.py

@@ -217,7 +217,6 @@ def arguments(self):
             argument(
                 self.argument_name,
                 self.input_type,
-                is_list=self.is_list and isinstance(self, DjangoCreateMutation),
             ),
         ]
 
@@ -274,6 +273,10 @@ def create(self, data: dict[str, Any], *, info: Info):
             )
 
 
+def get_vdata(data: Any) -> dict[str, Any]:
+    return vars(data).copy() if data is not None else {}
+
+
 def get_pk(
     data: dict[str, Any],
     *,
@@ -302,13 +305,25 @@ def resolver(
     ) -> Any:
         assert info is not None
 
+        data: list[Any] | Any = kwargs.get(self.argument_name)
+
+        if isinstance(data, list):
+            return [self.instance_level_update(info, kwargs, d) for d in data]
+
+        return self.instance_level_update(info, kwargs, data)
+
+    def instance_level_update(
+        self,
+        info: Info,
+        kwargs: dict[str, Any],
+        data: Any,
+    ) -> Any:
         model = self.django_model
         assert model is not None
 
-        data: Any = kwargs.get(self.argument_name)
-        vdata = vars(data).copy() if data is not None else {}
-
+        vdata = get_vdata(data)
         pk = get_pk(vdata, key_attr=self.key_attr)
+
         if pk not in (None, UNSET):  # noqa: PLR6201
             instance = get_with_perms(
                 pk,
@@ -368,7 +383,7 @@ def resolver(
         assert model is not None
 
         data: Any = kwargs.get(self.argument_name)
-        vdata = vars(data).copy() if data is not None else {}
+        vdata = get_vdata(data)
 
         pk = get_pk(vdata, key_attr=self.key_attr)
         if pk not in (None, UNSET):  # noqa: PLR6201

tests/mutations/conftest.py

@@ -35,7 +35,8 @@ class FruitFilter:
 @strawberry.type
 class Mutation:
     create_fruit: Fruit = mutations.create(FruitInput)
-    create_fruits: list[Fruit] = mutations.create(FruitInput)
+    create_fruits: list[Fruit] = mutations.create(list[FruitInput])
+    patch_fruits: list[Fruit] = mutations.update(list[FruitPartialInput], key_attr="id")
     update_fruits: list[Fruit] = mutations.update(
         FruitPartialInput, filters=FruitFilter, key_attr="id"
     )

tests/mutations/test_batch_mutations.py

@@ -0,0 +1,117 @@
+"""Tests for batched mutations.
+
+Batched mutations are mutations that mutate multiple objects at once.
+Mutations with a filter function or accept a list of objects that return a list.
+"""
+
+
+def test_batch_create(mutation, fruits):
+    result = mutation(
+        """
+        mutation {
+          fruits: createFruits(
+            data: [{ name: "banana" }, { name: "cherry" }]
+          ) {
+            id
+            name
+          }
+        }
+        """
+    )
+    assert not result.errors
+    assert result.data["fruits"] == [
+        {"id": "4", "name": "banana"},
+        {"id": "5", "name": "cherry"},
+    ]
+
+
+def test_batch_delete_with_filter(mutation, fruits):
+    result = mutation(
+        """
+        mutation($ids: [ID!]) {
+          fruits: deleteFruits(
+            filters: {id: {inList: $ids}}
+          ) {
+            id
+            name
+          }
+        }
+        """,
+        {"ids": ["2"]},
+    )
+    assert not result.errors
+    assert result.data["fruits"] == [
+        {"id": "2", "name": "raspberry"},
+    ]
+
+
+def test_batch_delete_with_filter_empty_list(mutation, fruits):
+    result = mutation(
+        """
+        {
+          fruits: deleteFruits(
+            filters: {id: {inList: []}}
+          ) {
+            id
+            name
+          }
+        }
+        """
+    )
+    assert not result.errors
+
+
+def test_batch_update_with_filter(mutation, fruits):
+    result = mutation(
+        """
+        {
+          fruits: updateFruits(
+            data: { name: "orange" }
+            filters: {id: {inList: [1]}}
+          ) {
+            id
+            name
+          }
+        }
+        """
+    )
+    assert not result.errors
+    assert result.data["fruits"] == [
+        {"id": "1", "name": "orange"},
+    ]
+
+
+def test_batch_update_with_filter_empty_list(mutation, fruits):
+    result = mutation(
+        """
+        {
+          fruits: updateFruits(
+            data: { name: "orange" }
+            filters: {id: {inList: []}}
+          ) {
+            id
+            name
+          }
+        }
+        """
+    )
+    assert not result.errors
+
+
+def test_batch_patch(mutation, fruits):
+    result = mutation(
+        """
+        {
+          fruits: patchFruits(
+            data: [{ id: 2, name: "orange" }]
+          ) {
+            id
+            name
+          }
+        }
+        """
+    )
+    assert not result.errors
+    assert result.data["fruits"] == [
+        {"id": "2", "name": "orange"},
+    ]