apm-agent-php: php apm 1.6.1 segfaults on a zend error/php warning

Describe the bug When inserting a continue into a for loop APM segfaults. PHP generally shows a warning, When I ran gdb it seems that zend throws and error. I really don’t think that apm should die on a warning without any useful information being exposed.

To Reproduce The below code triggers the segfault.

<?php

$alist = ['apple', 'banana', 'lemon', 'lime'];

print('Starting'. "\n");

foreach ($alist as $item) {
        switch ($item) {
                case 'apple':
                        print($item . "\n");
                        break;
                case 'banana':
                        print("more\n");
                        continue;
                default:
                        print("default\n");
        }
}
print("Ended\n");

Without APM PHP Warning: "continue" targeting switch is equivalent to "break". Did you mean to use "continue 2"? in /home/wayne/test.php on line 14 With APM Segmentation fault Expected behavior The php warning should be relayed to the logs somewhere.

GDB initial snippet

Reading symbols from /usr/sbin/php-fpm7.4...
Reading symbols from /usr/lib/debug/.build-id/4c/7489f921fc631b72accb27206c39024829c946.debug...
[New LWP 2076609]
[New LWP 2076638]
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
Core was generated by `php-fpm: pool www                                                            '.
Program terminated with signal SIGSEGV, Segmentation fault.
#0  0x00007f19d9243a1e in __vfscanf_internal (s=s@entry=0x7fffc73555d0, format=format@entry=0x7f19d93958f7 "%hu%n:%hu%n:%hu%n", argptr=argptr@entry=0x7fffc73555b8, mode_flags=mode_flags@entry=2)
    at vfscanf-internal.c:278
278	vfscanf-internal.c: No such file or directory.
[Current thread is 1 (Thread 0x7f19d717ba00 (LWP 2076609))]

GDB Offending lines

#42545 0x00007f19d3fc9836 in callPhpFunction () from /opt/elastic/apm-agent-php/extensions/elastic_apm-20190902.so
#42546 0x00007f19d3fc9e26 in callPhpFunctionRetVoid () from /opt/elastic/apm-agent-php/extensions/elastic_apm-20190902.so
#42547 0x00007f19d3fc772a in onPhpErrorToTracerPhpPart () from /opt/elastic/apm-agent-php/extensions/elastic_apm-20190902.so
#42548 0x00007f19d3fb60e7 in elasticApmZendErrorCallbackImpl () from /opt/elastic/apm-agent-php/extensions/elastic_apm-20190902.so
#42549 0x00007f19d3fb62de in elasticApmZendErrorCallback () from /opt/elastic/apm-agent-php/extensions/elastic_apm-20190902.so
#42550 0x000055a377dcf7b3 in zend_error_va_list (type=type@entry=2, error_filename=0x7f19c3eb3108 "/var/local/sac/app/Models/MemberBasket.php", error_lineno=292, format=format@entry=0x55a378072440 "\"continue\" targeting switch is equivalent to \"break\". Did you mean to use \"continue %ld\"?", args=args@entry=0x7fffc7b4faf0) at ./Zend/zend.c:1319
#42551 0x000055a377dcfd97 in zend_error (type=type@entry=2, format=format@entry=0x55a378072440 "\"continue\" targeting switch is equivalent to \"break\". Did you mean to use \"continue %ld\"?") at ./Zend/zend.c:1480

PHP FPM logs

[01-Dec-2022 10:33:13] WARNING: [pool www] child 2094944 exited on signal 11 (SIGSEGV - core dumped) after 33252.924112 seconds from start