fix(notes): honor explicit null when clearing optional fields

routes/note/note_routes.py

@@ -728,32 +728,35 @@ def setup_note_routes(task_scheduler=None, upload_handler=None):
             )
             if body.title is not None:
                 note.title = body.title
-            if body.content is not None:
+            # Omitted fields preserve their values; explicit null clears the
+            # nullable fields used by the editor's removal controls.
+            supplied = body.model_fields_set
+            if "content" in supplied:
                 note.content = body.content
-            if body.items is not None:
-                note.items = json.dumps(body.items)
+            if "items" in supplied:
+                note.items = json.dumps(body.items) if body.items is not None else None
                 flag_modified(note, "items")
             if body.note_type is not None:
                 note.note_type = body.note_type
-            if body.color is not None:
+            if "color" in supplied:
                 note.color = body.color
-            if body.label is not None:
+            if "label" in supplied:
                 note.label = body.label
             if body.pinned is not None:
                 note.pinned = body.pinned
             if body.archived is not None:
                 note.archived = body.archived
-            if body.due_date is not None:
+            if "due_date" in supplied:
                 note.due_date = body.due_date
-            if body.image_url is not None:
+            if "image_url" in supplied:
                 note.image_url = body.image_url
-            if body.gallery_id is not None:
+            if "gallery_id" in supplied:
                 note.gallery_id = body.gallery_id
             if body.repeat is not None:
                 note.repeat = body.repeat
             if body.sort_order is not None:
                 note.sort_order = body.sort_order
-            if body.agent_session_id is not None:
+            if "agent_session_id" in supplied:
                 note.agent_session_id = body.agent_session_id
 
             db.commit()

tests/test_notes_clear_optional_fields.py

@@ -0,0 +1,82 @@
+"""Explicit null must clear nullable note fields; omission must preserve them."""
+
+import pytest
+from fastapi import FastAPI
+from fastapi.testclient import TestClient
+
+from tests.helpers.database import disposable_database
+
+
+@pytest.fixture
+def client(tmp_path, monkeypatch):
+    import routes.note.note_routes as routes
+
+    with disposable_database(tmp_path) as factory:
+        monkeypatch.setattr(routes, "SessionLocal", factory)
+        app = FastAPI()
+
+        @app.middleware("http")
+        async def identity(request, call_next):
+            request.state.current_user = request.headers.get("x-test-user", "alice")
+            return await call_next(request)
+
+        monkeypatch.setattr(routes, "_scheduler_ref", None)
+        app.include_router(routes.setup_note_routes())
+        with TestClient(app) as api:
+            yield api
+
+
+@pytest.mark.parametrize("field,value", [
+    ("due_date", "2030-10-08T09:00:00"),
+    ("label", "home"),
+    ("image_url", "https://example.com/note.png"),
+    ("content", "Saved body"),
+    ("items", [{"text": "Saved item", "done": False}]),
+    ("color", "blue"),
+    ("gallery_id", "gallery-1"),
+    ("agent_session_id", "chat-1"),
+])
+def test_explicit_null_clears_saved_field(client, field, value):
+    created = client.post("/api/notes", json={"title": "Test note"})
+    assert created.status_code == 200, created.text
+    path = f"/api/notes/{created.json()['id']}"
+    populated = client.put(path, json={field: value})
+    assert populated.status_code == 200, populated.text
+    assert client.get(path).json()[field] == value
+
+    updated = client.put(path, json={field: None})
+    assert updated.status_code == 200, updated.text
+    saved = client.get(path)
+    assert saved.status_code == 200, saved.text
+    assert saved.json()[field] is None
+    assert updated.json()[field] is None
+
+
+def test_omitted_fields_survive_title_edit(client):
+    fields = {
+        "due_date": "2030-10-08T09:00:00",
+        "label": "home",
+        "image_url": "https://example.com/note.png",
+        "content": "Saved body",
+        "items": [{"text": "Saved item", "done": False}],
+        "color": "blue",
+        "gallery_id": "gallery-1",
+    }
+    created = client.post("/api/notes", json={"title": "Before", **fields})
+    assert created.status_code == 200, created.text
+    path = f"/api/notes/{created.json()['id']}"
+    updated = client.put(path, json={"title": "After"})
+    assert updated.status_code == 200, updated.text
+    saved = client.get(path).json()
+    assert saved["title"] == "After"
+    for field, value in fields.items():
+        assert saved[field] == value
+
+
+def test_null_update_cannot_clear_another_users_note(client):
+    created = client.post("/api/notes", json={"title": "Private", "label": "home"})
+    assert created.status_code == 200, created.text
+    path = f"/api/notes/{created.json()['id']}"
+    response = client.put(path, json={"label": None}, headers={"x-test-user": "bob"})
+    assert response.status_code == 404
+    assert client.get(path).json()["label"] == "home"