Nix build fails on Raspberry Pi running NixOS 23.11

[cor]

Running

nix build "git+ssh://[email protected]/ghostty-org/ghostty?ref=refs/heads/main&rev=e20b27de848afaa167c70d838a2f98f28c6ac0b5"

yields

error: builder for '/nix/store/87p5fhqq4jj5f6lp8hmhck8ajybjbzkz-ghostty-0.1.0.drv' failed with exit code 1;
       lathread 326 panic: reached unreachable code
       > Panicked during a panic. Aborting.
       > error: the following build command crashed:
       > /build/source/.zig-cache/o/c06f91bee3d22324ab360943bf0bb89f/build /nix/store/2cb5q6rp7qbvq46l3rq17glkrncsa4di-zig-0.13.0/bin/zig /build/source /build/source/.zig-cache /build/tmp.lumMibFHq1 --seed 0x33548109 -Z89673cd69e052791 -Dcpu=baseline -Doptimize=ReleaseFast -Dversion-string=0.1.0-e20b27d-nix
       For full logs, run 'nix log /nix/store/87p5fhqq4jj5f6lp8hmhck8ajybjbzkz-ghostty-0.1.0.drv'.

nix log /nix/store/87p5fhqq4jj5f6lp8hmhck8ajybjbzkz-ghostty-0.1.0.drv output:

Running phase: unpackPhase
unpacking source archive /nix/store/4948kxsl3j9s74iq3g9d97mshw1p218z-source
source root is source
@nix { "action": "setPhase", "phase": "patchPhase" }
Running phase: patchPhase
@nix { "action": "setPhase", "phase": "updateAutotoolsGnuConfigScriptsPhase" }
Running phase: updateAutotoolsGnuConfigScriptsPhase
@nix { "action": "setPhase", "phase": "buildPhase" }
Running phase: buildPhase
zig build flags: -Dcpu=baseline -Doptimize=ReleaseFast -Dversion-string=0.1.0-e20b27d-nix

System info:

• Raspberry Pi 5 8GB
• nixos-version => 23.11.20240629.4a1e673 (Tapir)
• github.com/cor/nixos-config/6b2d43bc0f5deb447275abc4eb9e2326531eeba4 nixosConfiguration raspberry-pi

Tried this in the last ~20 commits from current tip, all yield the same "Panicked during a panic. Aborting."

[cor]

Update: fails with the same error on NixOS 24.05

[cor]

Notably, the exact same build does succeed on both of my Macs, both also aarch64-linux, both also running NixOS 24.05 (in fact, they're built from the same flake)

[rhodes-b]

This is expected its an upstream issue with Zig detecting page sizes
ziglang/zig#20511

unfortunately right now you have to patch zig yourself
https://github.com/ziglang/zig/blob/8c232922bdf21d9936db94447da21ac0dd9ec319/lib/std/mem.zig#L17
by changing this line to 16 * 1024 (16k page size vs 4k which is normal for x86-64)

[adamcstephens]

Isn't raspberry pi already at 4k? I thought it was only Apple running at 16k.

[rhodes-b]

No you can see the same issue here in the discord RaspbianOS
https://discord.com/channels/1005603569187160125/1287827296329142383

That thread does say specifically a pi 5 so maybe the old ones have 4k pages

[jvoisin]

I have the same issue on Asahi Linux on an Apple M2:

jvoisin@chernabog 15:53 (main) ~/dev/ghostty zig build
thread 316845 panic: reached unreachable code
Panicked during a panic. Aborting.
error: the following build command crashed:
/home/jvoisin/dev/ghostty/.zig-cache/o/eb068cfe45fd6c8ce06185b729d2883c/build /usr/bin/zig /home/jvoisin/dev/ghostty /home/jvoisin/dev/ghostty/.zig-cache /home/jvoisin/.cache/zig --seed 0xc19051f1 -Z329352b1d7ccd6fa
[1]
jvoisin@chernabog 15:55 (main) ~/dev/ghostty 

The workaround specified here worked.

(If only for people landing here after some Google-fu)