Preserve JSON-like string parameters

src_cpp/py_connection.cpp

@@ -984,20 +984,6 @@ Value PyConnection::transformPythonValue(const py::handle& val) {
 }
 
 Value PyConnection::transformPythonValueFromParameter(const py::handle& val) {
-    if (py::isinstance<py::str>(val)) {
-        auto strVal = py::cast<std::string>(val);
-        if (!strVal.empty() && (strVal.front() == '{' || strVal.front() == '[')) {
-            auto jsonModule = py::module_::import("json");
-            try {
-                auto parsed = jsonModule.attr("loads")(val);
-                auto parsedType = pyLogicalTypeFromParameter(parsed);
-                if (parsedType.containsAny()) {
-                    return Value(LogicalType::JSON(), strVal);
-                }
-                return transformPythonValueFromParameterAs(parsed, parsedType);
-            } catch (...) {}
-        }
-    }
     auto type = pyLogicalTypeFromParameter(val);
     return transformPythonValueFromParameterAs(val, type);
 }

test/test_parameter.py

@@ -117,6 +117,25 @@ def test_str_param(conn_db_readonly: ConnDB) -> None:
     result.close()
 
 
+def test_json_like_string_param_round_trips_as_string(conn_db_empty: ConnDB) -> None:
+    conn, _ = conn_db_empty
+    conn.execute("CREATE NODE TABLE T(id STRING PRIMARY KEY, cfg STRING)")
+
+    value = '{"curator_enabled": false, "x": [1, 2, null]}'
+    result = conn.execute(
+        """
+        CREATE (t:T {id: "a"})
+        SET t.cfg = $cfg
+        RETURN t.cfg
+        """,
+        {"cfg": value},
+    )
+
+    assert result.get_next() == [value]
+    assert not result.has_next()
+    result.close()
+
+
 def test_date_param(conn_db_readonly: ConnDB) -> None:
     conn, _ = conn_db_readonly
     result = conn.execute(