feat(tags): prevent system tag modifications

api/conftest.py

@@ -165,13 +165,20 @@ def chargebee_subscription(organisation: Organisation) -> Subscription:
 
 
 @pytest.fixture()
-def project(organisation):
-    return Project.objects.create(name="Test Project", organisation=organisation)
+def tag(project):
+    return Tag.objects.create(label="tag", project=project, color="#000000")
 
 
 @pytest.fixture()
-def tag(project):
-    return Tag.objects.create(label="tag", project=project, color="#000000")
+def system_tag(project: Project) -> Tag:
+    return Tag.objects.create(
+        label="system-tag", project=project, color="#FFFFFF", is_system_tag=True
+    )
+
+
+@pytest.fixture()
+def project(organisation):
+    return Project.objects.create(name="Test Project", organisation=organisation)
 
 
 @pytest.fixture()
@@ -229,13 +236,17 @@ def with_project_permissions(
     """
 
     def _with_project_permissions(
-        permission_keys: list[str], project_id: typing.Optional[int] = None
+        permission_keys: list[str] = None,
+        project_id: typing.Optional[int] = None,
+        admin: bool = False,
     ) -> UserProjectPermission:
         project_id = project_id or project.id
         upp, __ = UserProjectPermission.objects.get_or_create(
-            project_id=project_id, user=staff_user
+            project_id=project_id, user=staff_user, admin=admin
         )
-        upp.permissions.add(*permission_keys)
+
+        if permission_keys:
+            upp.permissions.add(*permission_keys)
 
         return upp
 

api/projects/tags/serializers.py

@@ -1,3 +1,5 @@
+from typing import Any
+
 from rest_framework import serializers
 
 from projects.tags.models import Tag
@@ -18,3 +20,8 @@ class Meta:
             "type",
         )
         read_only_fields = ("project", "uuid", "is_system_tag", "type")
+
+    def validate(self, attrs: dict[str, Any]) -> dict[str, Any]:
+        if self.instance and self.instance.is_system_tag:
+            raise serializers.ValidationError("Cannot update a system tag.")
+        return super().validate(attrs)

api/projects/tags/views.py

@@ -1,4 +1,4 @@
-from rest_framework import viewsets
+from rest_framework import status, viewsets
 from rest_framework.decorators import action
 from rest_framework.generics import get_object_or_404
 from rest_framework.permissions import IsAuthenticated
@@ -36,6 +36,18 @@ def perform_update(self, serializer):
         project_id = int(self.kwargs["project_pk"])
         serializer.save(project_id=project_id)
 
+    def destroy(self, request: Request, *args, **kwargs):
+        instance = self.get_object()
+
+        if instance.is_system_tag:
+            return Response(
+                status=status.HTTP_400_BAD_REQUEST,
+                data={"message": "Cannot delete a system tag."},
+            )
+
+        self.perform_destroy(instance)
+        return Response(status=status.HTTP_204_NO_CONTENT)
+
     @action(
         detail=False,
         url_path=r"get-by-uuid/(?P<uuid>[0-9a-f-]+)",

api/tests/unit/projects/tags/test_views.py → api/tests/unit/projects/tags/test_unit_projects_tags_views.py

@@ -1,3 +1,5 @@
+import json
+
 import pytest
 from django.urls import reverse
 from pytest_lazyfixture import lazy_fixture
@@ -68,3 +70,51 @@ def test_get_tag_by__uuid_returns_200_for_user_with_view_project_permission(
     # Then
     assert response.status_code == status.HTTP_200_OK
     assert response.json()["uuid"] == str(tag.uuid)
+
+
+def test_cannot_delete_a_system_tag(
+    staff_client: APIClient,
+    with_project_permissions: WithProjectPermissionsCallable,
+    project: Project,
+    system_tag: Tag,
+) -> None:
+    # Given
+    url = reverse("api-v1:projects:tags-detail", args=(project.id, system_tag.id))
+
+    with_project_permissions(admin=True)
+
+    # When
+    response = staff_client.delete(url)
+
+    # Then
+    assert response.status_code == status.HTTP_400_BAD_REQUEST
+    assert response.json() == {"message": "Cannot delete a system tag."}
+
+
+def test_cannot_update_a_system_tag(
+    staff_client: APIClient,
+    with_project_permissions: WithProjectPermissionsCallable,
+    project: Project,
+    system_tag: Tag,
+):
+    # Given
+    url = reverse("api-v1:projects:tags-detail", args=(project.id, system_tag.id))
+
+    with_project_permissions(admin=True)
+
+    updated_label = f"{system_tag.label} updated"
+
+    data = {
+        "id": system_tag.id,
+        "color": system_tag.color,
+        "label": updated_label,
+        "project": system_tag.project_id,
+        "description": "",
+    }
+
+    # When
+    response = staff_client.put(url, json.dumps(data), content_type="application/json")
+
+    # Then
+    assert response.status_code == status.HTTP_400_BAD_REQUEST
+    assert response.json() == {"non_field_errors": ["Cannot update a system tag."]}