[php-src] Issue #13102: segfault in ReflectionNamedType::getName()

Issue: https://github.com/php/php-src/issues/13102 Author: ju1ius ### Description Hi, Given an _internal_ function named Acme\\example with the following return type (a resource): ```c zend_type return_type = { .ptr = NULL, .type_mask = MAY_BE_RESOURCE, }; ``` The following code: ```php <?php $fn = new ReflectionFunction('Acme\\example'); $ty = $fn->getReturnType()?->getName(); var_dump($ty); ``` Resulted in this output: ``` Segmentation fault (core dumped). ``` <details> <summary>GDB core dump:</summary> ```gdb Program terminated with signal SIGSEGV, Segmentation fault. #0 0x000055d3178b7c25 in zim_ReflectionNamedType_getName (execute_data=0x7f23f7c1a4c0, return_value=0x7f23f7c1a2d0) at /php-src/ext/reflection/php_reflection.c:3065 3065 RETURN_STR(zend_type_to_string_without_null(param->type)); (gdb) bt #0 0x000055d3178b7c25 in zim_ReflectionNamedType_getName (execute_data=0x7f23f7c1a4c0, return_value=0x7f23f7c1a2d0) at /php-src/ext/reflection/php_reflection.c:3065 #1 0x000055d317b6166a in ZEND_DO_FCALL_SPEC_RETVAL_USED_HANDLER () at /php-src/Zend/zend_vm_execute.h:1976 #2 0x000055d317be151c in execute_ex (ex=0x7f23f7c18020) at /php-src/Zend/zend_vm_execute.h:57246 #3 0x000055d317be5d57 in zend_execute (op_array=0x7f23f7c8c000, return_value=0x0) at /php-src/Zend/zend_vm_execute.h:61598 #4 0x000055d317b1ad40 in zend_execute_scripts (type=8, retval=0x0, file_count=3) at /php-src/Zend/zend.c:1881 #5 0x000055d317a562aa in php_execute_script (primary_file=0x7ffdf97060f0) at /php-src/main/main.c:2501 #6 0x000055d317ca8772 in do_cli (argc=6, argv=0x55d31a302b80) at /php-src/sapi/cli/php_cli.c:966 #7 0x000055d317ca953f in main (argc=6, argv=0x55d31a302b80) at /php-src/sapi/cli/php_cli.c:1340 ``` </details> But I expected this output instead: ``` string(8) "resource" ``` ### There are two problems here. The root is that zend_type_to_string does not handle the MAY_BE_RESOURCE flag, thus returning a NULL pointer in this case. Then, looking at the core dump, we can see that zim_ReflectionNamedType_getName does not handle the NULL pointer case, hence the segfault. A possible fix would be to make zend_type_to_string return "resource" when the type is a resource. Eventhough this type is not nameable in userland PHP, it is a real type in the engine, and this information can be valuable to expose to the reflection API. This would be a breaking change though (i.e. a codegen tool using reflection type info, would now generate an invalid type). Or just fix the null pointer dereference and call it a day... WDYT? ### PHP Version PHP 8.3-dev ### Operating System irrelevant