Our CI using the same docker image (heptacom/heptaconnect-pipeline:php81-8.0.0 based on debian:buster-slim) runs always into segfault running the coverage tests. Running locally on MacOS 14 I get into the same issue. When I bisect my way to the broken commit I noticed, that this https://github.com/xdebug/xdebug/commit/7d5e2e91f4b08eb673a20c8f57abfc1507889b27 broke it for php 8.2.17 but after reverting the changes I noticed changes in xdebug_execute_ex where a not operation was missing and has been moved to a wrapper with a comment https://github.com/xdebug/xdebug/blame/5115378c10642280f8f70034afd6401355f6e620/src/base/base.c#L857-L873 and having no not in this wrapper solves it for me. But I do not know why. I have also seen list structs where size and count where not 32 items apart (which seems to be the standard list memory append buffer size) but multiple thousands. So I assume it is just the wrong memory displayed at this struct.

The gdb and valgrind is from the pipeline image which has no debug symbols installed so I am not sure how helpful this is.

GDB
xdebug_branch_info_mark_reached (filename=0x7fabf65d1e60, function_name=function_name@entry=0x7ffd58dcd490 "Heptacom\HeptaConnect\Dataset\Base\Support\AbstractCollection->getIterator", op_array=op_array@entry=0x7fabf65df3b8,
opcode_nr=opcode_nr@entry=0) at ./build-8.1/src/coverage/branch_info.c:384
384 ./build-8.1/src/coverage/branch_info.c: No such file or directory.
(gdb) bt full
#0 xdebug_branch_info_mark_reached (filename=0x7fabf65d1e60, function_name=function_name@entry=0x7ffd58dcd490 "Heptacom\HeptaConnect\Dataset\Base\Support\AbstractCollection->getIterator", op_array=op_array@entry=0x7fabf65df3b8,
opcode_nr=opcode_nr@entry=0) at ./build-8.1/src/coverage/branch_info.c:384
i = 4331518
key = <optimized out>
dummy = 0x7ffd58dcd420
tail_fse = 0x557570420c30
file = 0x55756e3e3900
function = 0x55756c29bfa0
branch_info = 0x55756c29b770
#1 0x00007fabf9283507 in xdebug_print_opcode_info (cur_opcode=0x7fabf65d0e00, execute_data=<optimized out>, execute_data=<optimized out>) at ./build-8.1/src/coverage/code_coverage.c:171
op_array = 0x7fabf65df3b8
func_info = {object_class = 0x7fabf65c05a0, scope_class = 0x0, function = 0x7fabf6421c80, include_filename = 0x0, type = 3, internal = 0}
function_name = "Heptacom\HeptaConnect\Dataset\Base\Support\AbstractCollection->getIterator\000\000\000\000\000\000\030", '\000' <repeats 15 times>, "x\375\377\377\377\377\377\377\360E\023luU\000\000\000\000\000\000\000\000\000\000\243\325N\373\253\177\000\000x\375\377\377\377\377\377\377\340\233\005iuU\000\000@F\023luU\000\000\340\211muU\000\000\340\233\005iuU\000\000\214'\371\253\177\000\000\v\000\000\000\000\000\000\000P\207`muU\000\000\360K\004iuU\000\000"...
opnr = 0
0000002 0x00007fabf9284340 in xdebug_common_override_handler (execute_data=0x7fabf901b4e0) at ./build-8.1/src/coverage/code_coverage.c:239
lineno = 90
op_array = 0x7fabf65df3b8
cur_opcode = 0x7fabf65d0e00
0000003 0x000055756875e8b9 in ?? ()
No symbol table info available.
0000004 0x000055756875f310 in execute_ex ()
No symbol table info available.
0000005 0x00005575686eb34e in zend_call_function ()
No symbol table info available.
0000006 0x00005575686eb611 in zend_call_known_function ()
No symbol table info available.
0000007 0x000055756876bf48 in zend_user_it_new_iterator ()
No symbol table info available.
0000008 0x000055756876bf7e in zend_user_it_get_new_iterator ()

valgrind
==874== Memcheck, a memory error detector
==874== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al.
==874== Using Valgrind-3.14.0 and LibVEX; rerun with -h for copyright info
==874== Command: /usr/bin/php vendor/bin/phpunit --config=test/phpunit.xml --coverage-text
==874==
==874== Invalid read of size 4
==874== at 0x7B2E591: xdebug_branch_info_mark_reached (branch_info.c:383)
==874== by 0x7B2F506: xdebug_print_opcode_info.isra.4 (code_coverage.c:171)
==874== by 0x7B3033F: xdebug_common_override_handler (code_coverage.c:239)
==874== by 0x44F8B8: ??? (in /usr/bin/php8.1)
==874== by 0x45030F: execute_ex (in /usr/bin/php8.1)
==874== by 0x3DC34D: zend_call_function (in /usr/bin/php8.1)
==874== by 0x3DC610: zend_call_known_function (in /usr/bin/php8.1)
==874== by 0x45CF47: zend_user_it_new_iterator (in /usr/bin/php8.1)
==874== by 0x45CF7D: zend_user_it_get_new_iterator (in /usr/bin/php8.1)
==874== by 0x40A06A: ??? (in /usr/bin/php8.1)
==874== by 0x41BBCA: ??? (in /usr/bin/php8.1)
==874== by 0x45030F: execute_ex (in /usr/bin/php8.1)
==874== Address 0x13529294 is 4 bytes after a block of size 32 alloc'd
==874== at 0x483577F: malloc (vg_replace_malloc.c:299)
==874== by 0x7B22052: xdebug_llist_alloc (llist.c:26)
==874== by 0x7B1FF7B: xdebug_hash_alloc (hash.c:94)
==874== by 0x7B2E39D: xdebug_branch_find_paths (branch_info.c:328)
==874== by 0x7B2FF47: prefill_from_oparray (code_coverage.c:558)
==874== by 0x7B30292: prefill_from_function_table (code_coverage.c:577)
==874== by 0x7B30292: prefill_from_function_table (code_coverage.c:573)
==874== by 0x7B30292: prefill_from_class_table (code_coverage.c:599)
==874== by 0x7B30292: xdebug_prefill_code_coverage (code_coverage.c:627)
==874== by 0x7B303CC: xdebug_code_coverage_start_of_function (code_coverage.c:637)
==874== by 0x7B309FB: xdebug_coverage_execute_ex (code_coverage.c:984)
==874== by 0x7B1B64E: xdebug_execute_user_code_begin (base.c:777)
==874== by 0x480A68: ??? (in /usr/bin/php8.1)
==874== by 0x21E5CF: ??? (in /usr/bin/php8.1)
==874== by 0x45030F: execute_ex (in /usr/bin/php8.1)