Bug #77597 [Ver->Asn]: mysqli_fetch_field hangs scripts in PHP 7.3.2

Edit report at https://bugs.php.net/bug.php?id=77597&edit=1 ID: 77597 Updated by: nikic@php.net Reported by: ryan dot brothers at gmail dot com Summary: mysqli_fetch_field hangs scripts in PHP 7.3.2 -Status: Verified +Status: Assigned Type: Bug Package: MySQLi related Operating System: Linux PHP Version: 7.3.2 -Assigned To: +Assigned To: nikic Block user comment: N Private report: N Previous Comments: ------------------------------------------------------------------------ [2019-02-21 12:08:26] nikic@php.net From the debug trace, there's an infinite loop of php_mysqlnd_rowp_read_text_protocol_c calls: <mysqlnd_conn_data::store_result (total=5397 own=237 in_calls=5160) >mysqlnd_res::fetch_field | info : We have decode the whole result set to be able to satisfy this meta request | >mysqlnd_result_buffered_c::initialize_result_set_rest | | >php_mysqlnd_rowp_read_text_protocol_c | | | >php_mysqlnd_rowp_read_text_protocol_aux | | | <php_mysqlnd_rowp_read_text_protocol_aux (total=0 own=0 in_calls=0) | | <php_mysqlnd_rowp_read_text_protocol_c (total=38 own=38 in_calls=0) | | >php_mysqlnd_rowp_read_text_protocol_c | | | >php_mysqlnd_rowp_read_text_protocol_aux | | | <php_mysqlnd_rowp_read_text_protocol_aux (total=0 own=0 in_calls=0) | | <php_mysqlnd_rowp_read_text_protocol_c (total=37 own=37 in_calls=0) ... ------------------------------------------------------------------------ [2019-02-11 02:32:36] ryan dot brothers at gmail dot com Related To: Bug #68548 ------------------------------------------------------------------------ [2019-02-11 02:30:20] ryan dot brothers at gmail dot com Description: ------------ I am running into an issue with PHP 7.3.2 where calling mysqli_fetch_field hangs the script. The same script in PHP 7.2.15 runs successfully. It only occurs when calling store_result() with MYSQLI_STORE_RESULT_COPY_DATA It could be related to bug #68548 that I submitted a few years ago, but something changed in PHP 7.3.2 that causes the call to hang completely now. For the below test script, I'm using SQL: DROP TABLE IF EXISTS a; CREATE TABLE a (b int); INSERT INTO a VALUES (1),(2),(3),(4),(5),(6),(7),(8),(9); Test script: --------------- <?php $mysqli = new mysqli('localhost', 'test', 'test', 'test'); $mysqli->real_query("SELECT * FROM a"); $result = $mysqli->store_result(MYSQLI_STORE_RESULT_COPY_DATA); $field = $result->fetch_field(); Expected result: ---------------- Script runs and instantly exits. Actual result: -------------- In PHP 7.3.2 with MYSQLI_STORE_RESULT_COPY_DATA, the script hangs. In PHP 7.2.15 with MYSQLI_STORE_RESULT_COPY_DATA, the script runs and instantly exits. In PHP 7.3.2 without MYSQLI_STORE_RESULT_COPY_DATA, the script runs and instantly exits. In PHP 7.2.15 without MYSQLI_STORE_RESULT_COPY_DATA, the script runs and instantly exits. ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=77597&edit=1