[php-src] Issue #24561: session_write_close() returns true when the session data could not be written

Issue: https://github.com/php/php-src/issues/24561 Author: Marti2203 ### Description session_write_close() returns true even when the session data could not be written. The manual says it "Returns true on success or false on failure", but php_session_flush() returns true whenever the session was active, and php_session_save_current_state() does not report the write result. The following code: ```php <?php ini_set('session.use_cookies', 0); ini_set('session.cache_limiter', ''); class H implements SessionHandlerInterface { function open($p, $n): bool { return true; } function close(): bool { return true; } function read($id): string|false { return ''; } function write($id, $data): bool { echo "write() called, returning false\n"; return false; } function destroy($id): bool { return true; } function gc($m): int|false { return 0; } } session_set_save_handler(new H, false); session_id('abc'); session_start(); $_SESSION['x'] = 1; var_dump(session_write_close()); ``` Resulted in this output: ``` write() called, returning false Warning: session_write_close(): Failed to write session data using user defined save handler. (session.save_path: , handler: H::write) in ... on line 17 bool(true) ``` But I expected this output instead: ``` write() called, returning false Warning: session_write_close(): Failed to write session data using user defined save handler. (session.save_path: , handler: H::write) in ... on line 17 bool(false) ``` The same happens when encoding fails (e.g. a key containing |): the recently added ext/session/tests/session_write_close_encode_failure.phpt expects bool(true) after the "Failed to write session data" warning, so I'm not sure whether returning true here is intended (meaning "the session was closed") or whether session_write_close() should report the failed write. If it should, I'm happy to send a PR for master (php_session_save_current_state() returning its result and php_session_flush() passing it on), since it changes the return value. ### PHP Version PHP 8.4.28-dev (PHP-8.4 at b4ca62e317); same code on master ### Operating System Linux x86-64 This issue was found by an LLM-Enhanced Static Analysis Engine and verified manually.