Hyprland IPC Crash with hyprland/window

[aldenparker]

I am running into a seg fault when using hyprland/window with hyprland v0.54.1 on nixos. It fails to parse the new ipc is my guess as gdb is giving

Thread 9 ".waybar-wrapped" received signal SIGSEGV, Segmentation fault.
[Switching to Thread 0x7fffdb6fc6c0 (LWP 33538)]
0x00005555556f1952 in waybar::modules::hyprland::IPC::parseIPC(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&) ()

When I only use hyprland/workspaces it is fine, so I am guessing it is having trouble with parsing window ipcs.

Config for window (no special config for workspaces was used):

  "hyprland/window": {
  	"format": "{app_id} | {title:.80}",
    "separate-outputs": true,
    "icon": true,
  },

Ending log with debug and trace on:

2026-03-16 08:14:28.566] [debug] hyprland IPC received activewindow>>librewolf,New Issue — LibreWolf
fish: Job 1, 'WAYLAND_DEBUG=1 waybar -l trace' terminated by signal SIGSEGV (Address boundary error)

[jayshozie]

app_id is not one of the fields that can be used in the format according to official documentation; however, I was able to reproduce the segfault at both 0.15.0 and current upstream (6cb6873). This behavior looks like it's special to hyprland/window. I tested with different official and custom modules (where I tried to reference fields that does not exist in separate format strings including hyprland/workspaces with "format": "{name} {field_that_doesnt_exist}",) and they do not cause a segfault but rather log an error something like: [2026-03-19 19:19:49.055] [error] hyprland/workspaces: argument not found.