[ruby-core:126562] [Ruby Bug#22287] Prism aborts in pm_newline_list_append when requiring a file after fork

4 Sep 2026

      Issue #22287 has been updated by Earlopain (Earlopain _).

If OOM is at fault, we may want to backport https://github.com/ruby/ruby/commit/91be23cd961aa937701214ba5f50c698301c5e26 so that prism uses `ruby_xmalloc`.

On main this should not be a problem anymore because of the linked change but also because prism handles alloc failure at that place now.

----------------------------------------
Bug #22287: Prism aborts in pm_newline_list_append when requiring a file after fork
https://bugs.ruby-lang.org/issues/22287#change-118772

* Author: Morred (Laura Eck)
* Status: Open
* ruby -v: ruby 4.0.6 (2026-07-14 revision 03b6d3f889) +PRISM [arm64-darwin25]
* Backport: 3.3: UNKNOWN, 3.4: UNKNOWN, 4.0: UNKNOWN
----------------------------------------
Ruby crashed on me while I was running our precommit hooks, during the Rubocop step, with the following output:

```
Assertion failed: (list->size == 0 || newline_offset > list->offsets[list->size - 1]), function pm_newline_list_append, file pm_newline_list.c, line 51.
/Users/laura.eck/Projects/jeancaisse/lib/constants/feature_flags.rb: [BUG] Aborted at 0x000000018415c5e8
ruby 4.0.6 (2026-07-14 revision 03b6d3f889) +YJIT +PRISM [arm64-darwin25]

-- Crash Report log information --------------------------------------------
   See Crash Report log file in one of the following locations:
     * ~/Library/Logs/DiagnosticReports
     * /Library/Logs/DiagnosticReports
   for more details.
Don't forget to include the above Crash Report log file in bug reports.

-- Control frame information -----------------------------------------------
c:0055 p:---- s:0300 e:000299 l:y b:---- DUMMY  [FINISH]
c:0054 p:---- s:0297 e:000296 l:y b:0001 CFUNC  :require_relative
c:0053 p:0005 s:0292 e:000291 l:y b:0001 TOP    /Users/laura.eck/Projects/<redacted>/lib/cops/<redacted>/dx/feature_flag_setup.rb:3 [FINISH]
c:0052 p:---- s:0289 e:000288 l:y b:0001 CFUNC  :require
c:0051 p:0033 s:0284 e:000283 l:n b:---- BLOCK  /Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/ruby/4.0.0/bundled_gems.rb:60
c:0050 p:0023 s:0278 e:000277 l:n b:---- BLOCK  /Users/laura.eck/Projects/<redacted>/lib/cops.rb:46 [FINISH]
c:0049 p:0027 s:0274 e:000273 l:y b:0001 METHOD <internal:array>:228
c:0048 p:0096 s:0268 e:000267 l:y b:0001 TOP    /Users/laura.eck/Projects/<redacted>/lib/cops.rb:43 [FINISH]
c:0047 p:---- s:0265 e:000264 l:y b:0001 CFUNC  :require
c:0046 p:0033 s:0260 e:000259 l:n b:---- BLOCK  /Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/ruby/4.0.0/bundled_gems.rb:60
c:0045 p:0006 s:0254 e:000253 l:y b:0001 METHOD /Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/ruby/gems/4.0.0/gems/rubocop-1.87.0/lib/rubocop/feature_loader.rb:35
c:0044 p:0020 s:0248 e:000247 l:y b:0001 METHOD /Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/ruby/gems/4.0.0/gems/rubocop-1.87.0/lib/rubocop/feature_loader.rb:21
c:0043 p:0083 s:0241 e:000240 l:n b:---- BLOCK  /Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/ruby/gems/4.0.0/gems/rubocop-1.87.0/lib/rubocop/config_loader_resolver.rb:32 [FINISH]
c:0042 p:0027 s:0236 e:000235 l:y b:0001 METHOD <internal:array>:228
c:0041 p:0008 s:0230 e:000229 l:n b:---- BLOCK  /Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/ruby/gems/4.0.0/gems/rubocop-1.87.0/lib/rubocop/config_loader_resolver.rb:21
c:0040 p:0003 s:0226 e:000225 l:y b:0001 METHOD <internal:kernel>:91
c:0039 p:0017 s:0222 e:000221 l:y b:0001 METHOD /Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/ruby/gems/4.0.0/gems/rubocop-1.87.0/lib/rubocop/config_loader_resolver.rb:20
c:0038 p:0060 s:0215 e:000214 l:y b:0001 METHOD /Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/ruby/gems/4.0.0/gems/rubocop-1.87.0/lib/rubocop/config_loader.rb:63
c:0037 p:0022 s:0202 e:000201 l:y b:0001 METHOD /Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/ruby/gems/4.0.0/gems/rubocop-1.87.0/lib/rubocop/config_loader.rb:128
c:0036 p:0089 s:0194 e:000190 l:y b:0001 METHOD /Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/ruby/gems/4.0.0/gems/rubocop-1.87.0/lib/rubocop/config_store.rb:73
c:0035 p:0007 s:0185 e:000184 l:y b:0001 METHOD /Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/ruby/gems/4.0.0/gems/rubocop-1.87.0/lib/rubocop/config_store.rb:52
c:0034 p:0010 s:0181 e:000180 l:n b:---- BLOCK  /Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/ruby/gems/4.0.0/gems/rubocop-1.87.0/lib/rubocop/result_cache.rb:92
c:0033 p:0015 s:0178 e:000177 l:y b:0001 METHOD /Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/ruby/gems/4.0.0/gems/rubocop-1.87.0/lib/rubocop/cache_config.rb:9
c:0032 p:0023 s:0173 e:000172 l:y b:0001 METHOD /Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/ruby/gems/4.0.0/gems/rubocop-1.87.0/lib/rubocop/result_cache.rb:91
c:0031 p:0050 s:0166 e:000164 l:y b:0001 METHOD /Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/ruby/gems/4.0.0/gems/rubocop-1.87.0/lib/rubocop/cli.rb:172
c:0030 p:0018 s:0160 e:000159 l:n b:---- BLOCK  /Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/ruby/gems/4.0.0/gems/rubocop-1.87.0/lib/rubocop/cli.rb:49
c:0029 p:0011 s:0157 e:000156 l:y b:0001 METHOD /Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/ruby/gems/4.0.0/gems/rubocop-1.87.0/lib/rubocop/cli.rb:89
c:0028 p:0069 s:0147 e:000146 l:y b:0001 METHOD /Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/ruby/gems/4.0.0/gems/rubocop-1.87.0/lib/rubocop/cli.rb:45
c:0027 p:0035 s:0138 e:000137 l:y b:0001 METHOD /Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/ruby/gems/4.0.0/gems/rubocop-1.87.0/lib/rubocop/server/server_command/exec.rb:22
c:0026 p:0004 s:0133 e:000132 l:n b:---- BLOCK  /Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/ruby/gems/4.0.0/gems/rubocop-1.87.0/lib/rubocop/server/server_command/base.rb:24 [FINISH]
c:0025 p:---- s:0130 e:000129 l:y b:0001 CFUNC  :chdir
c:0024 p:0012 s:0125 e:000124 l:y b:0001 METHOD /Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/ruby/gems/4.0.0/gems/rubocop-1.87.0/lib/rubocop/server/server_command/base.rb:23
c:0023 p:0007 s:0121 e:000120 l:n b:---- BLOCK  /Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/ruby/gems/4.0.0/gems/rubocop-1.87.0/lib/rubocop/server/socket_reader.rb:33
c:0022 p:0059 s:0118 e:000117 l:y b:0001 METHOD /Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/ruby/gems/4.0.0/gems/rubocop-1.87.0/lib/rubocop/server/helper.rb:26
c:0021 p:0056 s:0106 e:000105 l:y b:0001 METHOD /Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/ruby/gems/4.0.0/gems/rubocop-1.87.0/lib/rubocop/server/socket_reader.rb:28
c:0020 p:0019 s:0100 e:000099 l:y b:0001 METHOD /Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/ruby/gems/4.0.0/gems/rubocop-1.87.0/lib/rubocop/server/core.rb:93
c:0019 p:0014 s:0094 e:000093 l:n b:---- BLOCK  /Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/ruby/gems/4.0.0/gems/rubocop-1.87.0/lib/rubocop/server/core.rb:68
c:0018 p:0012 s:0091 e:000090 l:y b:0001 METHOD /Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/ruby/gems/4.0.0/gems/rubocop-1.87.0/lib/rubocop/server/cache.rb:131
c:0017 p:0005 s:0087 e:000086 l:y b:0001 METHOD /Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/ruby/gems/4.0.0/gems/rubocop-1.87.0/lib/rubocop/server/core.rb:67
c:0016 p:0052 s:0083 e:000082 l:n b:---- BLOCK  /Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/ruby/gems/4.0.0/gems/rubocop-1.87.0/lib/rubocop/server/core.rb:56 [FINISH]
c:0015 p:---- s:0080 e:000079 l:y b:0001 CFUNC  :fork
c:0014 p:0008 s:0076 e:000075 l:y b:0001 METHOD /Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/ruby/gems/4.0.0/gems/rubocop-1.87.0/lib/rubocop/server/core.rb:47
c:0013 p:0042 s:0071 e:000070 l:y b:0001 METHOD /Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/ruby/gems/4.0.0/gems/rubocop-1.87.0/lib/rubocop/server/core.rb:39
c:0012 p:0063 s:0063 e:000062 l:n b:---- BLOCK  /Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/ruby/gems/4.0.0/gems/rubocop-1.87.0/lib/rubocop/server/client_command/start.rb:4
c:0011 p:0021 s:0057 e:000056 l:n b:---- BLOCK  /Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/ruby/gems/4.0.0/gems/rubocop-1.87.0/lib/rubocop/server/cache.rb:120 [FINISH]
c:0010 p:---- s:0052 e:000051 l:y b:0001 CFUNC  :open
c:0009 p:0010 s:0046 e:000045 l:y b:0001 METHOD /Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/ruby/gems/4.0.0/gems/rubocop-1.87.0/lib/rubocop/server/cache.rb:117
c:0008 p:0033 s:0042 e:000041 l:y b:0001 METHOD /Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/ruby/gems/4.0.0/gems/rubocop-1.87.0/lib/rubocop/server/client_command/start.rb:2
c:0007 p:0085 s:0038 e:000037 l:y b:0001 METHOD /Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/ruby/gems/4.0.0/gems/rubocop-1.87.0/lib/rubocop/server/cli.rb:93
c:0006 p:0156 s:0031 e:000030 l:y b:0001 METHOD /Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/ruby/gems/4.0.0/gems/rubocop-1.87.0/lib/rubocop/server/cli.rb:83
c:0005 p:0041 s:0023 e:000022 l:y b:0001 METHOD /Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/ruby/gems/4.0.0/gems/rubocop-1.87.0/lib/rubocop/server/cli.rb:49
c:0004 p:0043 s:0018 e:000017 l:y b:0001 TOP    /Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/ruby/gems/4.0.0/gems/rubocop-1.87.0/exe/rubocop:8 [FINISH]
c:0003 p:---- s:0013 e:000012 l:y b:0001 CFUNC  :load
c:0002 p:0111 s:0008 E:0019d0 l:n b:---- EVAL   bin/rubocop:52 [FINISH]
c:0001 p:0000 s:0003 E:002250 l:y b:---- DUMMY  [FINISH]

-- Ruby level backtrace information ----------------------------------------
bin/rubocop:52:in '<main>'
bin/rubocop:52:in 'load'
/Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/ruby/gems/4.0.0/gems/rubocop-1.87.0/exe/rubocop:8:in '<top (required)>'
/Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/ruby/gems/4.0.0/gems/rubocop-1.87.0/lib/rubocop/server/cli.rb:49:in 'run'
/Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/ruby/gems/4.0.0/gems/rubocop-1.87.0/lib/rubocop/server/cli.rb:83:in 'process_arguments'
/Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/ruby/gems/4.0.0/gems/rubocop-1.87.0/lib/rubocop/server/cli.rb:93:in 'run_command'
/Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/ruby/gems/4.0.0/gems/rubocop-1.87.0/lib/rubocop/server/client_command/start.rb:29:in 'run'
/Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/ruby/gems/4.0.0/gems/rubocop-1.87.0/lib/rubocop/server/cache.rb:117:in 'acquire_lock'
/Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/ruby/gems/4.0.0/gems/rubocop-1.87.0/lib/rubocop/server/cache.rb:117:in 'open'
/Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/ruby/gems/4.0.0/gems/rubocop-1.87.0/lib/rubocop/server/cache.rb:120:in 'block in acquire_lock'
/Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/ruby/gems/4.0.0/gems/rubocop-1.87.0/lib/rubocop/server/client_command/start.rb:42:in 'block in run'
/Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/ruby/gems/4.0.0/gems/rubocop-1.87.0/lib/rubocop/server/core.rb:39:in 'start'
/Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/ruby/gems/4.0.0/gems/rubocop-1.87.0/lib/rubocop/server/core.rb:47:in 'detach_server'
/Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/ruby/gems/4.0.0/gems/rubocop-1.87.0/lib/rubocop/server/core.rb:47:in 'fork'
/Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/ruby/gems/4.0.0/gems/rubocop-1.87.0/lib/rubocop/server/core.rb:56:in 'block in detach_server'
/Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/ruby/gems/4.0.0/gems/rubocop-1.87.0/lib/rubocop/server/core.rb:67:in 'process_input'
/Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/ruby/gems/4.0.0/gems/rubocop-1.87.0/lib/rubocop/server/cache.rb:131:in 'write_pid_file'
/Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/ruby/gems/4.0.0/gems/rubocop-1.87.0/lib/rubocop/server/core.rb:68:in 'block in process_input'
/Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/ruby/gems/4.0.0/gems/rubocop-1.87.0/lib/rubocop/server/core.rb:93:in 'read_socket'
/Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/ruby/gems/4.0.0/gems/rubocop-1.87.0/lib/rubocop/server/socket_reader.rb:28:in 'read!'
/Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/ruby/gems/4.0.0/gems/rubocop-1.87.0/lib/rubocop/server/helper.rb:26:in 'redirect'
/Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/ruby/gems/4.0.0/gems/rubocop-1.87.0/lib/rubocop/server/socket_reader.rb:33:in 'block in read!'
/Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/ruby/gems/4.0.0/gems/rubocop-1.87.0/lib/rubocop/server/server_command/base.rb:23:in 'run'
/Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/ruby/gems/4.0.0/gems/rubocop-1.87.0/lib/rubocop/server/server_command/base.rb:23:in 'chdir'
/Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/ruby/gems/4.0.0/gems/rubocop-1.87.0/lib/rubocop/server/server_command/base.rb:24:in 'block in run'
/Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/ruby/gems/4.0.0/gems/rubocop-1.87.0/lib/rubocop/server/server_command/exec.rb:22:in 'run'
/Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/ruby/gems/4.0.0/gems/rubocop-1.87.0/lib/rubocop/cli.rb:45:in 'run'
/Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/ruby/gems/4.0.0/gems/rubocop-1.87.0/lib/rubocop/cli.rb:89:in 'profile_if_needed'
/Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/ruby/gems/4.0.0/gems/rubocop-1.87.0/lib/rubocop/cli.rb:49:in 'block in run'
/Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/ruby/gems/4.0.0/gems/rubocop-1.87.0/lib/rubocop/cli.rb:172:in 'act_on_options'
/Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/ruby/gems/4.0.0/gems/rubocop-1.87.0/lib/rubocop/result_cache.rb:91:in 'cache_root'
/Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/ruby/gems/4.0.0/gems/rubocop-1.87.0/lib/rubocop/cache_config.rb:9:in 'root_dir'
/Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/ruby/gems/4.0.0/gems/rubocop-1.87.0/lib/rubocop/result_cache.rb:92:in 'block in cache_root'
/Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/ruby/gems/4.0.0/gems/rubocop-1.87.0/lib/rubocop/config_store.rb:52:in 'for_pwd'
/Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/ruby/gems/4.0.0/gems/rubocop-1.87.0/lib/rubocop/config_store.rb:73:in 'for_dir'
/Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/ruby/gems/4.0.0/gems/rubocop-1.87.0/lib/rubocop/config_loader.rb:128:in 'configuration_from_file'
/Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/ruby/gems/4.0.0/gems/rubocop-1.87.0/lib/rubocop/config_loader.rb:63:in 'load_file'
/Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/ruby/gems/4.0.0/gems/rubocop-1.87.0/lib/rubocop/config_loader_resolver.rb:20:in 'resolve_requires'
<internal:kernel>:91:in 'tap'
/Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/ruby/gems/4.0.0/gems/rubocop-1.87.0/lib/rubocop/config_loader_resolver.rb:21:in 'block in resolve_requires'
<internal:array>:228:in 'each'
/Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/ruby/gems/4.0.0/gems/rubocop-1.87.0/lib/rubocop/config_loader_resolver.rb:32:in 'block (2 levels) in resolve_requires'
/Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/ruby/gems/4.0.0/gems/rubocop-1.87.0/lib/rubocop/feature_loader.rb:21:in 'load'
/Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/ruby/gems/4.0.0/gems/rubocop-1.87.0/lib/rubocop/feature_loader.rb:35:in 'load'
/Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/ruby/4.0.0/bundled_gems.rb:60:in 'block (2 levels) in replace_require'
/Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/ruby/4.0.0/bundled_gems.rb:60:in 'require'
/Users/laura.eck/Projects/jeancaisse/lib/cops.rb:43:in '<top (required)>'
<internal:array>:228:in 'each'
/Users/laura.eck/Projects/<redacted>/lib/cops.rb:46:in 'block in <top (required)>'
/Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/ruby/4.0.0/bundled_gems.rb:60:in 'block (2 levels) in replace_require'
/Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/ruby/4.0.0/bundled_gems.rb:60:in 'require'
/Users/laura.eck/Projects/<redacted>/lib/cops/<redacted>/dx/feature_flag_setup.rb:3:in '<top (required)>'
/Users/laura.eck/Projects/<redacted>/lib/cops/<redacted>/dx/feature_flag_setup.rb:3:in 'require_relative'

-- Threading information ---------------------------------------------------
Total ractor count: 1
Ruby thread count for this ractor: 1

-- Machine register context ------------------------------------------------
  x0: 0x0000000000000000  x1: 0x0000000000000000  x2: 0x0000000000000000
  x3: 0x0000000000000000  x4: 0x0000000000000000  x5: 0x000000000000002e
  x6: 0x0000000000000000  x7: 0x0000000000000000 x18: 0x0000000000000000
 x19: 0x0000000000000006 x20: 0x0000000000000203 x21: 0x00000001f0bd6260
 x22: 0x0000000000000001 x23: 0x0000000101f471a1 x24: 0x00000001ee10a000
 x25: 0x0000000000000001 x26: 0x000000016eed28b0 x27: 0x0000000101f6d3f8
 x28: 0x0000000000000001  lr: 0x00000001841978d8  fp: 0x000000016eed23f0
  sp: 0x000000016eed23d0

-- C level backtrace information -------------------------------------------
/Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/libruby.4.0.dylib(rb_vm_bugreport+0xbc8) [0x101ce9fc4]
/Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/libruby.4.0.dylib(rb_bug_for_fatal_signal+0x10c) [0x101b066a0]
/Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/libruby.4.0.dylib(sigabrt+0x90) [0x101c3c228]
/usr/lib/system/libsystem_platform.dylib(_sigtramp+0x38) [0x1841a1744]
/usr/lib/system/libsystem_pthread.dylib(pthread_kill+0x128) [0x1841978d8]
/usr/lib/system/libsystem_c.dylib(abort+0x94) [0x18409d978]
[0x18409cbd4]
/Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/libruby.4.0.dylib(_pm_newline_list_append.cold.2+0x0) [0x101f163b8]
/Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/libruby.4.0.dylib(_pm_newline_list_append+0x0) [0x101d32b90]
/Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/libruby.4.0.dylib(_parser_lex+0xe1c) [0x101d36850]
/Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/libruby.4.0.dylib(_pm_parse+0x88) [0x101d34110]
/Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/libruby.4.0.dylib(_pm_parse_file+0xb0) [0x101a9184c]
/Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/libruby.4.0.dylib(_load_iseq_eval+0xa4) [0x101b7b17c]
/Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/libruby.4.0.dylib(_require_internal+0x31c) [0x101b79314]
/Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/libruby.4.0.dylib(_rb_require_string_internal+0x60) [0x101b78890]
/Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/libruby.4.0.dylib(_vm_call_cfunc_with_frame_+0xf0) [0x101cd97f0]
/Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/libruby.4.0.dylib(_vm_exec_core+0x2378) [0x101cbbd08]
/Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/libruby.4.0.dylib(_rb_vm_exec+0x268) [0x101cb7d2c]
/Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/libruby.4.0.dylib(_load_iseq_eval+0x230) [0x101b7b308]
/Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/libruby.4.0.dylib(_require_internal+0x31c) [0x101b79314]
/Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/libruby.4.0.dylib(_rb_require_string_internal+0x60) [0x101b78890]
/Users/laura.eck/.asdf/installs/ruby/4.0.6/lib/libruby.4.0.dylib(_rb_f_require+0x44) [0x101b78758]

-- Other runtime information -----------------------------------------------

* Loaded script: rubocop --server /Users/laura.eck/Projects/<redacted>

[I'm omitting the rest of the 3500 line output]
```

Crash report file is attached to this ticket. Please let me know if I can help out with any more information.

---Files--------------------------------
ruby-2026-09-03-133824.ips (20.8 KB)

-- 
https://bugs.ruby-lang.org/