pika-backup: init at 0.2.1

[dotlambda]

Motivation for this change

Things done

• Tested using sandboxing (nix.useSandbox on NixOS, or option sandbox in nix.conf on non-NixOS linux)
• Built on platform(s)
  • NixOS
  • macOS
  • other Linux distributions
• Tested via one or more NixOS test(s) if existing and applicable for the change (look inside nixos/tests)
• Tested compilation of all pkgs that depend on this change using nix-shell -p nixpkgs-review --run "nixpkgs-review wip"
• Tested execution of all binary files (usually in ./result/bin/)
• Determined the impact on package closure size (by running nix path-info -S before and after)
• Ensured that relevant documentation is up to date
• Fits CONTRIBUTING.md.

@danieldk Thanks for #112804!
cc @NixOS/gnome

[r-rmcgibbo]

Result of nixpkgs-review pr 115573 at 33af2e0 run on x86_64-linux 1

1 package built:

• pika-backup

1 suggestion:

• warning: missing-patch-comment

  Please add a comment on the line above, explaining the purpose of this patch.
  Near pkgs/applications/backup/pika-backup/default.nix:39:5:

     |
  39 |     (substituteAll {
     |     ^
  

[SuperSandro2000]

This can probably be replaced with substituteInPlace src/borg/utils.rs b/src/borg/utils.rs --replace 'Command::new("borg");' "Command::new(${borgbackup}/bin/borg);"

[dotlambda]

It can. But that makes it less obvious when things break. That's why I prefer patches.

[SuperSandro2000]

Substitute in place logs a warning when it can't find the pattern which nixpkgs hammering catches. Patches for simple things should be avoided because they clutter the repository and blow up the file count and size.

[jtojnar]

On the other hand, they are much easier to manage – you can simply apply them to the source code using git apply and then re-generate them using git diff. Manual substitute is more laborious and thus more prone to mistakes.

[danieldk]

I think there are arguments in favor of both approaches. So, I think we should favor what the package maintainer prefers. They have to maintain the patches/substitutions after all.