nixos-rebuld: error opening Git repo which uses reftable/sha256/compatobject sha1

[goyalyashpal]

titles / summaries

• nixos-rebuld: error opening Git repo which uses reftable refs, sha256 objects or even sha1 compat objects.

details

high level steps to reproduce the error:

1. i initialised a git repo at /xxx as follows to store my nixos config files in. the /etc/nixos/configuration.nix is symlinked to file in this repo.

git init --ref-format=reftable --object-format=sha256 --initial-branch=main /xxx

2. now i want to switch to using flakes. so, i created flake.nix in this repo, and create symlink in /etc/nixos/flake.nix to point to this.

3. running sudo nixos-rebuild dry-build results in following error.

building the system configuration...
error:
       … while fetching the input 'git+file:///xxx'

       error: opening Git repository '"/xxx"': unsupported extension name extensions.refstorage
[ble: exit 1]

4. i tried fixing it with creating a dummy repo /yyy as follows, and symlinking the /etc/nixos/flake.nix to it:

git clone /etc-nixos .

## Tried with these too:
# git clone --depth=1 --config extensions.compatObjectFormat=sha1 file:///yyy/ .
# git clone --depth=1 --config=extensions.objectFormat=sha1 file:///etc-nixos .

5. now, it shows the error:

$ sudo nixos-rebuild dry-build
building the system configuration...
error:
       … while fetching the input 'git+file:///yyy'

       error: opening Git repository '"/yyy"': unknown object format 'sha256'
[ble: exit 1]

or
+

$ sudo nixos-rebuild dry-build
building the system configuration...
error:
       … while fetching the input 'git+file:///yyy?shallow=1'

       error: opening Git repository '"/yyy"': unsupported extension name extensions.compatobjectformat
[ble: exit 1]

environment

$ nix-info -m
 - system: `"x86_64-linux"`
 - host os: `Linux 6.6.77, NixOS, 24.11 (Vicuna), 24.11.714614.c618e28f7025`
 - multi-user?: `yes`
 - sandbox: `yes`
 - version: `nix-env (Nix) 2.24.12`
 - nixpkgs: `/nix/var/nix/profiles/per-user/root/channels/nixos`

[eclairevoyant]

This should be closed as duplicate of NixOS/nix#11561

[goyalyashpal]

yeah, i was thinking that this doesnt really belong to neither packages, nor modules. but the executables on nixos.

thanks for guiding.