Hi, thanks for handling f file consition in LuaMetaTeX. While playing with that, I encountered a potential bug in the latest LuaMetaTeX version: If handle_error_hook is executed and returns any number, LuaMetaTeX segfaults. (I'm pretty sure that this still worked with the previous version) Minimal ConTeXt example: \enabledirectives[system.quitonerror=false] \directlua{ print(callbacks.register('handle_error_hook', function(...) return 3 end)) } \undefined % Trigger an error \starttext \stoptext This triggers [...] system > ConTeXt ver: 2020.07.31 10:20 LMTX fmt: 2020.7.31 int: english/english [...] tex error > tex error on line 7 in file ./test_empty_input.tex: ! Undefined control sequence l.7 \undefined [...] 9 \stoptext segmentation fault (core dumped) /home/marcel/lmtx-install/tex/texmf-linux-64/bin/luametatex cont-yes.mkiv valgrind suggests that this is caused by an attempt to access a null pointer: ==382632== Invalid write of size 4 ==382632== at 0x1A581F: ??? (in /home/marcel/lmtx-install/tex/texmf-linux-64/bin/luametatex) ==382632== by 0x1A662F: ??? (in /home/marcel/lmtx-install/tex/texmf-linux-64/bin/luametatex) ==382632== by 0x14BAA8: ??? (in /home/marcel/lmtx-install/tex/texmf-linux-64/bin/luametatex) ==382632== by 0x1DA50E: ??? (in /home/marcel/lmtx-install/tex/texmf-linux-64/bin/luametatex) ==382632== by 0x1DA802: ??? (in /home/marcel/lmtx-install/tex/texmf-linux-64/bin/luametatex) ==382632== by 0x15F956: ??? (in /home/marcel/lmtx-install/tex/texmf-linux-64/bin/luametatex) ==382632== by 0x156E2E: ??? (in /home/marcel/lmtx-install/tex/texmf-linux-64/bin/luametatex) ==382632== by 0x121E97: ??? (in /home/marcel/lmtx-install/tex/texmf-linux-64/bin/luametatex) ==382632== by 0x4A16001: (below main) (in /usr/lib/libc-2.31.so) ==382632== Address 0x0 is not stack'd, malloc'd or (recently) free'd ==382632== ==382632== ==382632== Process terminating with default action of signal 11 (SIGSEGV): dumping core ==382632== Access not within mapped region at address 0x0 ==382632== at 0x1A581F: ??? (in /home/marcel/lmtx-install/tex/texmf-linux-64/bin/luametatex) ==382632== by 0x1A662F: ??? (in /home/marcel/lmtx-install/tex/texmf-linux-64/bin/luametatex) ==382632== by 0x14BAA8: ??? (in /home/marcel/lmtx-install/tex/texmf-linux-64/bin/luametatex) ==382632== by 0x1DA50E: ??? (in /home/marcel/lmtx-install/tex/texmf-linux-64/bin/luametatex) ==382632== by 0x1DA802: ??? (in /home/marcel/lmtx-install/tex/texmf-linux-64/bin/luametatex) ==382632== by 0x15F956: ??? (in /home/marcel/lmtx-install/tex/texmf-linux-64/bin/luametatex) ==382632== by 0x156E2E: ??? (in /home/marcel/lmtx-install/tex/texmf-linux-64/bin/luametatex) ==382632== by 0x121E97: ??? (in /home/marcel/lmtx-install/tex/texmf-linux-64/bin/luametatex) ==382632== by 0x4A16001: (below main) (in /usr/lib/libc-2.31.so) That me know if you are interested in the coredump. Best regards, Marcel