git diff call fails, ".../default.nix" is outside repository at "/repo/path"

[colemickens]

nix-update \
--flake \
packages.x86_64-linux.foot \
--version \
branch=master \
--commit \
--override-filename \
./pkgs/foot/metadata.nix

results in:

[the nix expr that nix-update evals + prints is omitted, except the last line of the output here:]
$ git diff --color=never --word-diff=porcelain -- /nix/store/hhwdvcdgz7qz2prms49lr1h82v5qagxp-source/pkgs/foot/default.nix
fatal: /nix/store/hhwdvcdgz7qz2prms49lr1h82v5qagxp-source/pkgs/foot/default.nix: '/nix/store/hhwdvcdgz7qz2prms49lr1h82v5qagxp-source/pkgs/foot/default.nix' is outside repository at '/home/cole/code/nixpkgs-wayland
[traceback omitted]

(note this is not with master of nixpkgs-wayland, but a branch where I'm experimenting with nix-update instead of my old bespoke update script)

Not quite sure what's going on here? I'm passing a relative path for the file for it to try and update, I'm not doing anything to make an out of repo reference, as far as I can tell.

[colemickens]

So, very interestingly, if I manually revert foot to an old rev and run it, it works! But it fails on the second run.

First run produces commit:

commit b02274d75440280a62b851289f87e5e7d0c9b7d7
Author: Cole Mickens <cole.mickens@gmail.com>
Date:   Thu Sep 19 14:43:11 2024 -0700

    packages.x86_64-linux.foot: 1.18.1-unstable-2024-09-13 -> 1.18.1-unstable-2024-09-15

    Diff: https://codeberg.org/dnkl/foot/compare/33f3818520bd5f7a063f64442c54d41625332aeb...297cb370aa3f9e9a9093415217be410fae6fccfa

    Changelog: https://codeberg.org/dnkl/foot/releases/tag/1.18.1-unstable-2024-09-15

diff --git a/pkgs/foot/metadata.nix b/pkgs/foot/metadata.nix
index e6e366da..affc7618 100644
--- a/pkgs/foot/metadata.nix
+++ b/pkgs/foot/metadata.nix
@@ -5,7 +5,7 @@ rec {
   repo = "foot";
   repo_git = "https://${domain}/${owner}/${repo}";
   branch = "master";
-  version = "1.18.1-unstable-2024-09-13";
-  rev = "33f3818520bd5f7a063f64442c54d41625332aeb";
-  sha256 = "sha256-iNj14FO5Lr1UU/h0MdOgWor7xo/lJz1CunYbI9yg8Ls=";
+  version = "1.18.1-unstable-2024-09-15";
+  rev = "297cb370aa3f9e9a9093415217be410fae6fccfa";
+  sha256 = "sha256-H/YdqM2pQfyoUWIEou0Xm0P5LxDoO4N5eb5Ymvtplls=";
 }

Which looks pretty much exactly right.

But, a subsequent run (that I'd expect to be an idempotent/no-op) produces the error shown above.

[colemickens]

Note, also, I find it odd that it is diffing default.nix even when I override the file? But also it works the first try somehow so?

[colemickens]

In the successful case:

Update 1.18.1-unstable-2024-09-13 -> 1.18.1-unstable-2024-09-15 in ./pkgs/foot/metadata.nix
$ nix-build --expr let src = (let flake = builtins.getFlake "/home/cole/code/nixpkgs-wayland"; in flake.packages.${builtins.currentSystem}."packages"."x86_64-linux"."foot" or flake."packages"."x86_64-linux"."foot").src; in (src.overrideAttrs or (f: src // f src)) (_: { outputHash = ""; outputHashAlgo = "sha256"; }) --extra-experimental-features flakes nix-command
Package maintainers:
  - Lukas Epple (@sternenseemann)
$ git -C /home/cole/code/nixpkgs-wayland diff -- ./pkgs/foot/metadata.nix

ref: https://github.com/Mic92/nix-update/blob/7dd0e4467c571ebb7e53d9e3d40c49f75473efdf/nix_update/update.py#L394-L396

[Mic92]

Note, also, I find it odd that it is diffing default.nix even when I override the file? But also it works the first try somehow so?

The override file flag was added later and may not be taken into account by the diff command.