Change named param binding to re-use value for same name

Relates to crate/crate#19193

Author: mfussenegger

src/crate/client/cursor.py

@@ -49,19 +49,25 @@ def _convert_named_to_positional(
         params = {"a": 1, "b": 2}
         # returns: ("SELECT * FROM t WHERE a = ? AND b = ?", [1, 2])
     """
-    positional: t.List[t.Any] = []
+    positions = {}
+    idx = 1
+    new_params = []
+    for k, v in params.items():
+        positions[k] = idx
+        new_params.append(v)
+        idx += 1
 
     def _replace(match: "re.Match[str]") -> str:
         name = match.group(1)
         if name not in params:
             raise ProgrammingError(
                 f"Named parameter '{name}' not found in the parameters dict"
             )
-        positional.append(params[name])
-        return "?"
+        position = positions[name]
+        return f"${position}"
 
     converted_sql = _NAMED_PARAM_RE.sub(_replace, sql)
-    return converted_sql, positional
+    return converted_sql, new_params
 
 
 class Cursor:

tests/client/test_cursor.py

@@ -503,7 +503,7 @@ def test_execute_with_named_params(mocked_connection):
         {"a": 1, "b": 2},
     )
     mocked_connection.client.sql.assert_called_once_with(
-        "SELECT * FROM t WHERE a = ? AND b = ?", [1, 2], None
+        "SELECT * FROM t WHERE a = $1 AND b = $2", [1, 2], None
     )
 
 
@@ -515,7 +515,7 @@ def test_execute_with_named_params_repeated(mocked_connection):
     cursor = mocked_connection.cursor()
     cursor.execute("SELECT %(x)s, %(x)s", {"x": 42})
     mocked_connection.client.sql.assert_called_once_with(
-        "SELECT ?, ?", [42, 42], None
+        "SELECT $1, $1", [42], None
     )