fix(tui-gateway): harden pending-title retry and user errors

Retry persisting queued titles on session.title reads and map title validation failures to a user-facing 4022 code instead of generic 5007.

tests/test_tui_gateway_server.py

@@ -375,6 +375,34 @@ def test_session_title_get_falls_back_to_pending_when_db_read_throws(monkeypatch
         server._sessions.pop("sid", None)
 
 
+def test_session_title_get_retries_persist_for_pending_title(monkeypatch):
+    class _FakeDB:
+        def __init__(self):
+            self.title = ""
+
+        def get_session_title(self, _key):
+            return self.title
+
+        def set_session_title(self, _key, title):
+            self.title = title
+            return True
+
+        def get_session(self, _key):
+            return {"id": _key, "title": self.title}
+
+    db = _FakeDB()
+    server._sessions["sid"] = _session(pending_title="queued title")
+    monkeypatch.setattr(server, "_get_db", lambda: db)
+    try:
+        resp = server.handle_request(
+            {"id": "1", "method": "session.title", "params": {"session_id": "sid"}}
+        )
+        assert resp["result"]["title"] == "queued title"
+        assert server._sessions["sid"]["pending_title"] is None
+    finally:
+        server._sessions.pop("sid", None)
+
+
 def test_session_title_rejects_empty_title_with_specific_error_code(monkeypatch):
     class _FakeDB:
         def get_session_title(self, _key):
@@ -396,6 +424,34 @@ def test_session_title_rejects_empty_title_with_specific_error_code(monkeypatch)
         server._sessions.pop("sid", None)
 
 
+def test_session_title_set_maps_valueerror_to_user_error(monkeypatch):
+    class _FakeDB:
+        def get_session_title(self, _key):
+            return ""
+
+        def get_session(self, _key):
+            return {"id": _key}
+
+        def set_session_title(self, _key, _title):
+            raise ValueError("Title already in use")
+
+    server._sessions["sid"] = _session()
+    monkeypatch.setattr(server, "_get_db", lambda: _FakeDB())
+    try:
+        resp = server.handle_request(
+            {
+                "id": "1",
+                "method": "session.title",
+                "params": {"session_id": "sid", "title": "dup"},
+            }
+        )
+        assert "error" in resp
+        assert resp["error"]["code"] == 4022
+        assert "already in use" in resp["error"]["message"]
+    finally:
+        server._sessions.pop("sid", None)
+
+
 def test_session_title_set_errors_when_row_lookup_fails_after_noop(monkeypatch):
     class _FakeDB:
         def get_session_title(self, _key):

tui_gateway/server.py

@@ -1765,7 +1765,21 @@ def _(rid, params: dict) -> dict:
     if "title" not in params:
         fallback = session.get("pending_title") or ""
         try:
-            resolved_title = db.get_session_title(key) or fallback
+            resolved_title = db.get_session_title(key) or ""
+            if not resolved_title and fallback:
+                if db.set_session_title(key, fallback):
+                    session["pending_title"] = None
+                    resolved_title = fallback
+                else:
+                    existing_row = db.get_session(key)
+                    existing_title = ((existing_row or {}).get("title") or "").strip()
+                    if existing_title == fallback:
+                        session["pending_title"] = None
+                        resolved_title = fallback
+                    else:
+                        resolved_title = fallback
+            elif resolved_title:
+                session["pending_title"] = None
         except Exception:
             resolved_title = fallback
         return _ok(
@@ -1796,6 +1810,8 @@ def _(rid, params: dict) -> dict:
             )
         session["pending_title"] = title
         return _ok(rid, {"pending": True, "title": title})
+    except ValueError as e:
+        return _err(rid, 4022, str(e))
     except Exception as e:
         return _err(rid, 5007, str(e))