fix: accept UUID strings for WorkItemDetail labels and assignees

Plane v1.3.0 changed the API to return labels and assignees as UUID
strings instead of expanded objects. WorkItemDetail typed these as
list[Label] and list[UserLite] respectively, causing a Pydantic
ValidationError on any retrieve_work_item call against a v1.3.0+ instance.

Change both fields to list[str] | list[T] = [] so they accept either
representation, and default to [] for sparse responses (consistent with
WorkItemExpand and the fix in makeplane#28).

Adds 8 unit tests covering: UUID strings, expanded objects, empty lists,
omitted fields, and that name remains required.

Author: vdaluz

plane/models/work_items.py

@@ -53,8 +53,8 @@ class WorkItemDetail(BaseModel):
     model_config = ConfigDict(extra="allow", populate_by_name=True)
 
     id: str | None = None
-    assignees: list[UserLite]
-    labels: list[Label]
+    assignees: list[str] | list[UserLite] = []
+    labels: list[str] | list[Label] = []
     type_id: str | None = None
     created_at: str | None = None
     updated_at: str | None = None

tests/unit/test_work_item_detail_types.py

@@ -0,0 +1,109 @@
+"""Unit tests for WorkItemDetail model type compatibility with Plane v1.3.0+.
+
+Plane v1.3.0 changed the API to return labels and assignees as UUID strings
+instead of expanded objects, even when not using the `fields` sparse parameter.
+These tests verify that WorkItemDetail handles both representations.
+"""
+
+import pytest
+from pydantic import ValidationError
+
+from plane.models.work_items import WorkItemDetail
+
+
+MINIMAL_WORK_ITEM = {
+    "id": "ef6bf853-fecb-433e-a4e3-8546e60abebd",
+    "name": "Test issue",
+    "sequence_id": 1,
+}
+
+
+class TestWorkItemDetailLabelsAssigneesTypes:
+    """WorkItemDetail should accept labels/assignees as UUID strings or objects."""
+
+    def test_labels_as_uuid_strings(self) -> None:
+        """Plane v1.3.0 returns labels as UUID strings — must not raise."""
+        data = {
+            **MINIMAL_WORK_ITEM,
+            "labels": ["f6a24a78-a275-4fd1-a777-0e9e0e99dbef"],
+            "assignees": [],
+        }
+        item = WorkItemDetail(**data)
+        assert item.labels == ["f6a24a78-a275-4fd1-a777-0e9e0e99dbef"]
+
+    def test_assignees_as_uuid_strings(self) -> None:
+        """Plane v1.3.0 returns assignees as UUID strings — must not raise."""
+        data = {
+            **MINIMAL_WORK_ITEM,
+            "labels": [],
+            "assignees": ["48b05854-3e71-44f0-9fcb-7a5d6887f5ec"],
+        }
+        item = WorkItemDetail(**data)
+        assert item.assignees == ["48b05854-3e71-44f0-9fcb-7a5d6887f5ec"]
+
+    def test_both_as_uuid_strings(self) -> None:
+        """Both fields as UUID strings simultaneously."""
+        data = {
+            **MINIMAL_WORK_ITEM,
+            "labels": [
+                "f6a24a78-a275-4fd1-a777-0e9e0e99dbef",
+                "a8509ac8-7c71-4b9e-9a4a-623ef2c2365b",
+            ],
+            "assignees": ["48b05854-3e71-44f0-9fcb-7a5d6887f5ec"],
+        }
+        item = WorkItemDetail(**data)
+        assert len(item.labels) == 2
+        assert len(item.assignees) == 1
+
+    def test_labels_as_objects(self) -> None:
+        """Expanded label objects (pre-v1.3.0 behavior) still parse correctly."""
+        data = {
+            **MINIMAL_WORK_ITEM,
+            "labels": [
+                {
+                    "id": "f6a24a78-a275-4fd1-a777-0e9e0e99dbef",
+                    "name": "v3",
+                    "color": "#FF6900",
+                    "project": "9aa02e26-3b44-4fd2-96f9-015aa9ee7a52",
+                    "workspace": "0f4d413a-a164-4168-aa31-abbdaa0aecd1",
+                }
+            ],
+            "assignees": [],
+        }
+        item = WorkItemDetail(**data)
+        assert len(item.labels) == 1
+
+    def test_assignees_as_objects(self) -> None:
+        """Expanded assignee objects (pre-v1.3.0 behavior) still parse correctly."""
+        data = {
+            **MINIMAL_WORK_ITEM,
+            "labels": [],
+            "assignees": [
+                {
+                    "id": "48b05854-3e71-44f0-9fcb-7a5d6887f5ec",
+                    "display_name": "vic",
+                    "avatar": None,
+                    "is_bot": False,
+                }
+            ],
+        }
+        item = WorkItemDetail(**data)
+        assert len(item.assignees) == 1
+
+    def test_empty_lists(self) -> None:
+        """Empty lists for both fields are valid."""
+        data = {**MINIMAL_WORK_ITEM, "labels": [], "assignees": []}
+        item = WorkItemDetail(**data)
+        assert item.labels == []
+        assert item.assignees == []
+
+    def test_fields_omitted_defaults_to_empty(self) -> None:
+        """Fields absent from response default to empty lists (sparse responses)."""
+        item = WorkItemDetail(**MINIMAL_WORK_ITEM)
+        assert item.labels == []
+        assert item.assignees == []
+
+    def test_name_still_required(self) -> None:
+        """name remains a required field — no over-relaxation."""
+        with pytest.raises(ValidationError):
+            WorkItemDetail(id="abc", labels=[], assignees=[])