Fix empty parameter list [] being converted to None

The truthiness check `if parameters` converts an empty list to None,
since `bool([])` is False. Use `if parameters is not None` instead.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: antoineleclair

src/dqlitedbapi/aio/cursor.py

@@ -59,7 +59,7 @@ async def execute(
         self._check_closed()
 
         conn = await self._connection._ensure_connection()
-        params = list(parameters) if parameters else None
+        params = list(parameters) if parameters is not None else None
 
         # Determine if this is a query that returns rows
         normalized = operation.strip().upper()

src/dqlitedbapi/cursor.py

@@ -71,7 +71,7 @@ def execute(self, operation: str, parameters: Sequence[Any] | None = None) -> "C
     async def _execute_async(self, operation: str, parameters: Sequence[Any] | None = None) -> None:
         """Async implementation of execute."""
         conn = await self._connection._get_async_connection()
-        params = list(parameters) if parameters else None
+        params = list(parameters) if parameters is not None else None
 
         # Determine if this is a query that returns rows
         normalized = operation.strip().upper()

tests/test_param_conversion.py

@@ -0,0 +1,67 @@
+"""Tests for parameter conversion in cursor execute."""
+
+import asyncio
+from unittest.mock import AsyncMock, MagicMock
+
+from dqlitedbapi.cursor import Cursor
+
+
+def _make_mock_connection() -> MagicMock:
+    """Create a mock Connection with a fake async connection."""
+    mock_protocol = AsyncMock()
+    mock_protocol.exec_sql = AsyncMock(return_value=(0, 0))
+    mock_protocol.query_sql = AsyncMock(return_value=(["id"], [[1]]))
+
+    mock_async_conn = AsyncMock()
+    mock_async_conn._protocol = mock_protocol
+    mock_async_conn._db_id = 0
+
+    mock_conn = MagicMock()
+
+    async def get_async_conn() -> AsyncMock:
+        return mock_async_conn
+
+    mock_conn._get_async_connection = get_async_conn
+
+    # Make _run_sync execute the coroutine in a new event loop
+    def run_sync(coro: object) -> object:
+        return asyncio.get_event_loop_policy().new_event_loop().run_until_complete(coro)
+
+    mock_conn._run_sync = run_sync
+
+    return mock_conn, mock_protocol
+
+
+class TestParameterConversion:
+    def test_empty_list_not_converted_to_none(self) -> None:
+        """Passing parameters=[] should not convert to None."""
+        mock_conn, mock_protocol = _make_mock_connection()
+        cursor = Cursor(mock_conn)
+
+        cursor.execute("INSERT INTO t VALUES (?)", [])
+
+        mock_protocol.exec_sql.assert_called_once()
+        call_args = mock_protocol.exec_sql.call_args[0]
+        assert call_args[2] == [], f"Expected [], got {call_args[2]!r}"
+
+    def test_none_params_stays_none(self) -> None:
+        """Passing parameters=None should stay None."""
+        mock_conn, mock_protocol = _make_mock_connection()
+        cursor = Cursor(mock_conn)
+
+        cursor.execute("INSERT INTO t VALUES (1)")
+
+        mock_protocol.exec_sql.assert_called_once()
+        call_args = mock_protocol.exec_sql.call_args[0]
+        assert call_args[2] is None, f"Expected None, got {call_args[2]!r}"
+
+    def test_nonempty_params_converted_to_list(self) -> None:
+        """Passing parameters=(1, 2) should convert to [1, 2]."""
+        mock_conn, mock_protocol = _make_mock_connection()
+        cursor = Cursor(mock_conn)
+
+        cursor.execute("INSERT INTO t VALUES (?, ?)", (1, 2))
+
+        mock_protocol.exec_sql.assert_called_once()
+        call_args = mock_protocol.exec_sql.call_args[0]
+        assert call_args[2] == [1, 2], f"Expected [1, 2], got {call_args[2]!r}"