fix: resolve ADBC nullable timestamp and Spanner cache hit issues

- ADBC store: Use separate SQL path when expires_at is None to avoid
  Arrow 'na' type mapping error (Arrow can't infer type from Python None)
- Cache: Preserve list type for execute_many parameters on cache hit
  (Spanner driver requires list, not tuple)

Author: cofin

sqlspec/adapters/adbc/litestar/store.py

@@ -311,18 +311,41 @@ def _set(self, key: str, value: "str | bytes", expires_in: "int | timedelta | No
                 VALUES ({p1}, {p2}, {p3})
                 """
             elif dialect in {"postgres", "postgresql"}:
-                # Use explicit CAST for nullable timestamp to avoid Arrow 'na' type mapping issues
+                # ADBC Arrow driver cannot infer type from Python None, causing 'na' type error.
+                # Use separate SQL statements for NULL vs non-NULL expires_at to avoid the issue.
+                if expires_at is None:
+                    sql = f"""
+                    INSERT INTO {self._table_name} (session_id, data, expires_at)
+                    VALUES ({p1}, {p2}, NULL)
+                    ON CONFLICT (session_id) DO UPDATE
+                    SET data = EXCLUDED.data, expires_at = NULL
+                    """
+                    with self._config.provide_session() as driver:
+                        driver.execute(sql, key, data)
+                        driver.commit()
+                    return
                 sql = f"""
                 INSERT INTO {self._table_name} (session_id, data, expires_at)
-                VALUES ({p1}, {p2}, CAST({p3} AS TIMESTAMPTZ))
+                VALUES ({p1}, {p2}, {p3})
                 ON CONFLICT (session_id) DO UPDATE
                 SET data = EXCLUDED.data, expires_at = EXCLUDED.expires_at
                 """
             else:
-                # DuckDB: Use explicit CAST for nullable timestamp to avoid Arrow 'na' type mapping issues
+                # DuckDB: Same issue with Arrow 'na' type for None values
+                if expires_at is None:
+                    sql = f"""
+                    INSERT INTO {self._table_name} (session_id, data, expires_at)
+                    VALUES ({p1}, {p2}, NULL)
+                    ON CONFLICT (session_id) DO UPDATE
+                    SET data = EXCLUDED.data, expires_at = NULL
+                    """
+                    with self._config.provide_session() as driver:
+                        driver.execute(sql, key, data)
+                        driver.commit()
+                    return
                 sql = f"""
                 INSERT INTO {self._table_name} (session_id, data, expires_at)
-                VALUES ({p1}, {p2}, CAST({p3} AS TIMESTAMP))
+                VALUES ({p1}, {p2}, {p3})
                 ON CONFLICT (session_id) DO UPDATE
                 SET data = EXCLUDED.data, expires_at = EXCLUDED.expires_at
                 """

sqlspec/driver/_common.py

@@ -1390,15 +1390,13 @@ def _get_compiled_statement(
                     prepared_statement=prepared_statement,
                 )
                 # Return cached SQL metadata but with newly processed parameters
-                cached_parameters = (
-                    tuple(prepared_parameters) if isinstance(prepared_parameters, list) else prepared_parameters
-                )
+                # Preserve list type for execute_many operations (some drivers require list, not tuple)
                 updated_cached = CachedStatement(
                     compiled_sql=cached_result.compiled_sql,
-                    parameters=cached_parameters,
+                    parameters=prepared_parameters,
                     expression=cached_result.expression,
                 )
-                return updated_cached, cached_parameters
+                return updated_cached, prepared_parameters
 
         prepared_statement = self.prepare_statement(statement, statement_config=statement_config)
         compiled_sql, execution_parameters = prepared_statement.compile()