From 69b2e5e0b23098a36cd57ea11df7481291364307 Mon Sep 17 00:00:00 2001
From: Jeremy Fleischman <me@jfly.fyi>
Date: Sun, 5 Jul 2026 09:37:25 -0700
Subject: [PATCH] nixos/fish: `programs.fish.generateCompletions` fix spaces in
 filenames

`linux-manual` has this fun filename in it:

```console
$ find -L $(nix-build -A linux-manual) -name 'station table - introduction.9.gz'
/nix/store/q45mzaksp2ll04c363mxpyi252j6anrq-linux-manual-7.1.3/share/man/man9/station table - introduction.9.gz
```

Our `find ... | xargs ...` didn't handle this nicely, and would vomit in the
following way:

`repro.nix`:

```nix
$ cat repro.nix
let
  pkgs = import ./. { };
  nixosConfig = pkgs.nixos (
    { config, pkgs, ... }: {
      system.stateVersion = config.system.nixos.release;

      programs.fish.enable = true;
      programs.fish.generateCompletions = true;

      environment.systemPackages = [ pkgs.linux-manual ];
    }
  );
in
nixosConfig.config.environment.etc."fish/generated_completions".source
```

The crash:

```console
$ nix-build repro.nix
these 2 derivations will be built:
  /nix/store/qs213n0r723w59jdvfz5w87azd3wh405-linux-manual-7.1.3_fish-completions.drv
  /nix/store/1pwps30drz71icj5v4rdiaarmh37xcn8-system_fish-completions.drv
building '/nix/store/qs213n0r723w59jdvfz5w87azd3wh405-linux-manual-7.1.3_fish-completions.drv'...
usage: create_manpage_completions.py [-h] [-c CLEANUP_IN] [-d DIRECTORY] [-k]
                                     [-m] [-p] [-s] [-v {0,1,2}] [-z]
                                     [file_paths ...]
create_manpage_completions.py: error: unrecognized arguments: -introduction.9.gz /nix/store/q45mzaksp2ll04c363mxpyi252j6anrq-linux-manual-7.1.3/share/man/man9/DRBD State macros.9.gz /nix/store/q45mzaksp2ll04c363mxpyi252j6anrq-linux-manual-7.1.3/share/man/man9/DRM Client usage stats.9.gz /nix/store/q45mzaksp2ll04c363mxpyi252j6anrq-linux-manual-7.1.3/share/man/man9/DRM RAS Node Management.9.gz /nix/store/q45mzaksp2ll04c363mxpyi252j6anrq-linux-manual-7.1.3/share/man/man9/DRM_ACCEL_FOPS.9.gz
```

This fix is simple, use the `find -print0 ... | xargs -0 ...` pattern.
---
 nixos/modules/programs/fish.nix | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/nixos/modules/programs/fish.nix b/nixos/modules/programs/fish.nix
index b425ed4028f1..734d19bdc92d 100644
--- a/nixos/modules/programs/fish.nix
+++ b/nixos/modules/programs/fish.nix
@@ -293,8 +293,8 @@ in
                 ''
                   mkdir -p $out
                   if [ -d $package/share/man ]; then
-                    find -L $package/share/man -type f \
-                      | xargs ${pkgs.python3.pythonOnBuildForHost.interpreter} \
+                    find -L $package/share/man -type f -print0 \
+                      | xargs -0 ${pkgs.python3.pythonOnBuildForHost.interpreter} \
                           ${generator}/create_manpage_completions.py --directory $out \
                           >/dev/null
                   fi