Allow setting integration_filter to null in webhooks internal API (#4011)

Fixes https://github.com/grafana/oncall/issues/4006

CHANGELOG.md

@@ -15,6 +15,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Fixed
 
 - Fix selecting values in notification settings ([#9566](https://github.com/grafana/support-escalations/issues/9566))
+- Allow setting integration_filter to null in webhooks internal API ([#4011](https://github.com/grafana/oncall/pull/4011))
 
 ## v1.3.109 (2024-03-04)
 

engine/apps/api/serializers/webhook.py

@@ -117,6 +117,10 @@ class WebhookSerializer(LabelsSerializerMixin, serializers.ModelSerializer):
             data["password"] = webhook.password
         if data.get("authorization_header") == WEBHOOK_FIELD_PLACEHOLDER:
             data["authorization_header"] = webhook.authorization_header
+
+        if not data.get("integration_filter"):
+            data["integration_filter"] = []
+
         return super().to_internal_value(data)
 
     def _validate_template_field(self, template):
@@ -185,13 +189,13 @@ class WebhookSerializer(LabelsSerializerMixin, serializers.ModelSerializer):
             for controlled_field in preset_metadata.controlled_fields:
                 if controlled_field in self.initial_data:
                     if self.instance:
-                        if self.initial_data[controlled_field] is not None and self.initial_data[
-                            controlled_field
-                        ] != getattr(self.instance, controlled_field):
+                        if bool(self.initial_data[controlled_field]) and self.initial_data[controlled_field] != getattr(
+                            self.instance, controlled_field
+                        ):
                             raise serializers.ValidationError(
                                 detail=f"{controlled_field} is controlled by preset, cannot update"
                             )
-                    elif self.initial_data[controlled_field] is not None:
+                    elif bool(self.initial_data[controlled_field]):
                         raise serializers.ValidationError(
                             detail=f"{controlled_field} is controlled by preset, cannot create"
                         )

engine/apps/api/tests/test_webhooks.py

@@ -354,6 +354,24 @@ def test_webhook_integration_filter(webhook_internal_api_setup, make_alert_recei
     assert list(webhook.filtered_integrations.all()) == []
     assert response.json()["integration_filter"] == []
 
+    # clear filter also works if set to None
+    url = reverse("api-internal:webhooks-detail", kwargs={"pk": webhook.public_primary_key})
+    data = {
+        "name": "github_button_updated",
+        "url": "https://github.com/",
+        "trigger_type": Webhook.TRIGGER_ALERT_GROUP_CREATED,
+        "http_method": "POST",
+        "team": None,
+        "integration_filter": None,
+    }
+    response = client.put(
+        url, data=json.dumps(data), content_type="application/json", **make_user_auth_headers(user, token)
+    )
+    webhook.refresh_from_db()
+    assert response.status_code == status.HTTP_200_OK
+    assert list(webhook.filtered_integrations.all()) == []
+    assert response.json()["integration_filter"] == []
+
 
 @pytest.mark.django_db
 @pytest.mark.parametrize(