fix(mcp): fix dashboard slug null and execute_sql encoding error (#38710)

tests/unit_tests/mcp_service/sql_lab/tool/test_execute_sql.py

@@ -23,6 +23,7 @@ and response conversion logic.
 """
 
 import logging
+from decimal import Decimal
 from typing import Any
 from unittest.mock import MagicMock, Mock, patch
 
@@ -883,3 +884,208 @@ class TestExecuteSql:
             options = call_args[0][1]
             assert options.cache is not None
             assert options.cache.force_refresh is True
+
+    @patch("superset.security_manager")
+    @patch("superset.db")
+    @pytest.mark.asyncio
+    async def test_execute_sql_bytes_in_dataframe(
+        self, mock_db, mock_security_manager, mcp_server
+    ):
+        """Test that bytes/memoryview values in DataFrame are sanitized for JSON.
+
+        Regression test: execute_sql fails with 'encoding without a string
+        argument' when queries return binary/bytea data.
+        """
+        mock_database = _mock_database()
+        df = pd.DataFrame(
+            [
+                {
+                    "id": 1,
+                    "name": "test",
+                    "utf8_data": b"hello world",
+                    "binary_data": b"\x00\x01\x02\xff",
+                },
+            ]
+        )
+        mock_database.execute.return_value = QueryResult(
+            status=QueryStatus.SUCCESS,
+            statements=[
+                StatementResult(
+                    original_sql="SELECT * FROM files",
+                    executed_sql="SELECT * FROM files",
+                    data=df,
+                    row_count=1,
+                    execution_time_ms=5.0,
+                )
+            ],
+            query_id=None,
+            total_execution_time_ms=5.0,
+            is_cached=False,
+        )
+        mock_db.session.query.return_value.filter_by.return_value.first.return_value = (
+            mock_database
+        )
+        mock_security_manager.can_access_database.return_value = True
+
+        request = {
+            "database_id": 1,
+            "sql": "SELECT * FROM files",
+            "limit": 10,
+        }
+
+        async with Client(mcp_server) as client:
+            result = await client.call_tool("execute_sql", {"request": request})
+
+            data = result.structured_content
+            assert data["success"] is True
+            assert data["row_count"] == 1
+            row = data["rows"][0]
+            # UTF-8 decodable bytes should become string
+            assert row["utf8_data"] == "hello world"
+            # Non-UTF-8 bytes should become hex
+            assert row["binary_data"] == "000102ff"
+
+    @patch("superset.security_manager")
+    @patch("superset.db")
+    @pytest.mark.asyncio
+    async def test_execute_sql_decimal_in_dataframe(
+        self, mock_db, mock_security_manager, mcp_server
+    ):
+        """Test that Decimal values in DataFrame are converted to float for JSON.
+
+        Regression test: execute_sql fails with 'encoding without a string
+        argument' when queries return Decimal types (common with SUM/AVG).
+        """
+        mock_database = _mock_database()
+        df = pd.DataFrame(
+            [
+                {
+                    "id": 1,
+                    "price": Decimal("19.99"),
+                    "total": Decimal("1234567.89"),
+                },
+            ]
+        )
+        mock_database.execute.return_value = QueryResult(
+            status=QueryStatus.SUCCESS,
+            statements=[
+                StatementResult(
+                    original_sql="SELECT * FROM orders",
+                    executed_sql="SELECT * FROM orders",
+                    data=df,
+                    row_count=1,
+                    execution_time_ms=5.0,
+                )
+            ],
+            query_id=None,
+            total_execution_time_ms=5.0,
+            is_cached=False,
+        )
+        mock_db.session.query.return_value.filter_by.return_value.first.return_value = (
+            mock_database
+        )
+        mock_security_manager.can_access_database.return_value = True
+
+        request = {
+            "database_id": 1,
+            "sql": "SELECT * FROM orders",
+            "limit": 10,
+        }
+
+        async with Client(mcp_server) as client:
+            result = await client.call_tool("execute_sql", {"request": request})
+
+            data = result.structured_content
+            assert data["success"] is True
+            assert data["row_count"] == 1
+            row = data["rows"][0]
+            assert row["price"] == 19.99
+            assert row["total"] == 1234567.89
+            assert isinstance(row["price"], float)
+
+
+class TestSanitizeRowValues:
+    """Unit tests for _sanitize_row_values helper function."""
+
+    def test_sanitize_utf8_bytes(self):
+        from superset.mcp_service.sql_lab.tool.execute_sql import _sanitize_row_values
+
+        rows = [{"data": b"hello"}]
+        _sanitize_row_values(rows)
+        assert rows[0]["data"] == "hello"
+
+    def test_sanitize_non_utf8_bytes(self):
+        from superset.mcp_service.sql_lab.tool.execute_sql import _sanitize_row_values
+
+        rows = [{"data": b"\x00\xff"}]
+        _sanitize_row_values(rows)
+        assert rows[0]["data"] == "00ff"
+
+    def test_sanitize_memoryview(self):
+        from superset.mcp_service.sql_lab.tool.execute_sql import _sanitize_row_values
+
+        rows = [{"data": memoryview(b"test")}]
+        _sanitize_row_values(rows)
+        assert rows[0]["data"] == "test"
+
+    def test_sanitize_decimal(self):
+        from superset.mcp_service.sql_lab.tool.execute_sql import _sanitize_row_values
+
+        rows = [{"price": Decimal("19.99"), "count": Decimal("42")}]
+        _sanitize_row_values(rows)
+        assert rows[0]["price"] == 19.99
+        assert isinstance(rows[0]["price"], float)
+        assert rows[0]["count"] == 42.0
+
+    def test_sanitize_custom_type_uses_str(self):
+        from superset.mcp_service.sql_lab.tool.execute_sql import _sanitize_row_values
+
+        class CustomType:
+            def __str__(self):
+                return "custom_value"
+
+        rows = [{"data": CustomType()}]
+        _sanitize_row_values(rows)
+        assert rows[0]["data"] == "custom_value"
+
+    def test_preserves_json_serializable_types(self):
+        from superset.mcp_service.sql_lab.tool.execute_sql import _sanitize_row_values
+
+        rows = [
+            {
+                "str_val": "hello",
+                "int_val": 42,
+                "float_val": 3.14,
+                "bool_val": True,
+                "none_val": None,
+                "list_val": [1, 2],
+                "dict_val": {"a": 1},
+            }
+        ]
+        original = [dict(row) for row in rows]
+        _sanitize_row_values(rows)
+        assert rows == original
+
+    def test_sanitize_empty_rows(self):
+        from superset.mcp_service.sql_lab.tool.execute_sql import _sanitize_row_values
+
+        rows: list[dict[str, Any]] = []
+        _sanitize_row_values(rows)
+        assert rows == []
+
+    def test_sanitize_mixed_types_in_single_row(self):
+        from superset.mcp_service.sql_lab.tool.execute_sql import _sanitize_row_values
+
+        rows = [
+            {
+                "id": 1,
+                "name": "test",
+                "price": Decimal("9.99"),
+                "blob": b"\x00\x01\x02\xff",
+            }
+        ]
+        _sanitize_row_values(rows)
+        assert rows[0]["id"] == 1
+        assert rows[0]["name"] == "test"
+        assert rows[0]["price"] == 9.99
+        assert rows[0]["blob"] == "000102ff"