WritableResourceStream::handleWrite() enters infinite loop on broken TLS socket (EPIPE without PHP warning)

Commencez dans src/WritableResourceStream.php, au niveau du guard de handleWrite() vers la ligne 151, puis suivez l’impact des résultats de fwrite() et des avertissements capturés sur le tampon d’écriture et le listener. Reproduisez le problème avec un ReactPHP SecureServer et un client TLS arrêté brutalement alors que des écritures sont en file d’attente. Le travail est terminé lorsqu’une écriture false silencieuse ferme le flux, tandis qu’une écriture à zéro conserve le comportement existant dépendant des avertissements et ne provoque plus de boucle CPU.

On PHP 8.x with react/socket's SecureServer (TLS), when a remote client disconnects abruptly, epoll reports EPOLLOUT|EPOLLHUP on the dead socket FD. WritableResourceStream::handleWrite() calls fwrite(), which returns false because the kernel write() returns -1 EPIPE. However, PHP's OpenSSL stream wrapper does not call php_error_docref() for SSL_ERROR_SYSCALL+EPIPE errors in all code paths. The set_error_handler capture therefore gets nothing ($error === null).

The guard evaluates to false, so close() is never called. WritableResourceStream then silently passes false to substr() (implicit cast to 0 in non-strict mode), leaving the write buffer unchanged and the write listener active. epoll keeps returning EPOLLOUT|EPOLLHUP, fwrite() keeps returning false silently - 100% CPU lockup.

Reproduction: use react/socket SecureServer with TLS, kill a client with kill -9 while the server has queued writes to that client.

Fix: separate the $sent === false case (hard error - always close) from $sent === 0 (may be transient EAGAIN/WANT_WRITE - only close when PHP warning is present):

// Before
if (($sent === 0 || $sent === false) && $error !== null) {

// After
if ($sent === false || ($sent === 0 && $error !== null)) {

This issue was investigated with the help of AI, but the 100% CPU usage issue is real and after applying the above fix on production, it seems to have disappeared.