Fix _perm_cache processing

strawberry_django/utils/query.py

@@ -125,11 +125,10 @@ def filter_for_user_q(
         raise ValueError(f"Cannot mix app_labels ({app_labels!r})")
 
     # Small optimization if the user's permissions are cached
-    perm_cache = getattr(user, "_perm_cache", None)
-    if perm_cache is not None:  # pragma:nocover
+    perm_cache: Optional[Set[str]] = getattr(user, "_perm_cache", None)
+    if perm_cache is not None:
         f = any if any_perm else all
-        user_perms: Set[str] = {p.codename for p in perm_cache}
-        if f(p in user_perms for p in perms_list):
+        if f(p in perm_cache for p in perms_list):
             return qs
 
     q = Q()

tests/projects/schema.py

@@ -15,6 +15,7 @@
     OuterRef,
     Prefetch,
     Q,
+    Subquery,
 )
 from django.db.models.functions import Now
 from django.db.models.query import QuerySet
@@ -34,6 +35,7 @@
     IsAuthenticated,
     IsStaff,
     IsSuperuser,
+    filter_for_user,
 )
 from strawberry_django.relay import ListConnectionWithTotalCount
 
@@ -205,6 +207,22 @@ def milestone_name(self) -> str:
     def milestone_name_without_only_optimization(self) -> str:
         return self.milestone.name
 
+    @strawberry_django.field(
+        annotate={
+            "_private_name": lambda info: Subquery(
+                filter_for_user(
+                    Issue.objects.all(),
+                    info.context.request.user,
+                    ["projects.view_issue"],
+                )
+                .filter(id=OuterRef("pk"))
+                .values("name")[:1],
+            ),
+        },
+    )
+    def private_name(self, root: Issue) -> Optional[str]:
+        return root._private_name  # type: ignore
+
 
 @strawberry_django.type(Tag)
 class TagType(relay.Node):

tests/projects/snapshots/schema.gql

@@ -258,6 +258,7 @@ type IssueType implements Node {
   ): FavoriteTypeConnection!
   milestoneName: String!
   milestoneNameWithoutOnlyOptimization: String!
+  privateName: String
 }
 
 """A connection to a list of items."""

tests/test_permissions.py

@@ -6,6 +6,8 @@
 from strawberry.relay import to_base64
 from typing_extensions import Literal, TypeAlias
 
+from strawberry_django.optimizer import DjangoOptimizerExtension
+
 from .projects.faker import (
     GroupFactory,
     IssueFactory,
@@ -282,6 +284,49 @@ def test_superuser_required_optional(db, gql_client: GraphQLTestClient):
         }
 
 
+@pytest.mark.django_db(transaction=True)
+def test_perm_cached(db, gql_client: GraphQLTestClient):
+    """Validates that the permission caching mechanism correctly stores permissions as a set of strings.
+
+    The test targets the `_perm_cache` attribute used in `utils/query.py`. It verifies that
+    the attribute behaves as expected, holding a `Set[str]` that represents permission
+    codenames, rather than direct Permission objects.
+
+    This test addresses a regression captured by the following error:
+
+    ```
+    user_perms: Set[str] = {p.codename for p in perm_cache}
+                          ^^^^^^^^^^
+    AttributeError: 'str' object has no attribute 'codename'
+    ```
+    """
+    query = """
+    query Issue ($id: GlobalID!) {
+        issuePermRequired (id: $id) {
+          id
+          privateName
+        }
+    }
+    """
+    issue = IssueFactory.create(name="Test")
+
+    # User with permission
+    user_with_perm = UserFactory.create()
+    user_with_perm.user_permissions.add(
+        Permission.objects.get(codename="view_issue"),
+    )
+    assign_perm("view_issue", user_with_perm, issue)
+    with gql_client.login(user_with_perm):
+        if DjangoOptimizerExtension.enabled.get():
+            res = gql_client.query(query, {"id": to_base64("IssueType", issue.pk)})
+            assert res.data == {
+                "issuePermRequired": {
+                    "id": to_base64("IssueType", issue.pk),
+                    "privateName": issue.name,
+                },
+            }
+
+
 @pytest.mark.django_db(transaction=True)
 @pytest.mark.parametrize("kind", perm_kinds)
 def test_perm_required(db, gql_client: GraphQLTestClient, kind: PermKind):