nixos/tsm-client: Fix multi-value dsm.sys options

[lluchs]

A configuration such as:

programs.tsmClient.servers.backup.domain = [ "/dir1" "/dir2" ];

...would previously result in an error ("cannot coerce a list to a string"), since makeDsmSysLines would return a nested list.

Description of changes

Things done

• Built on platform(s)
  • x86_64-linux
  • aarch64-linux
  • x86_64-darwin
  • aarch64-darwin
• For non-Linux: Is sandboxing enabled in nix.conf? (See Nix manual)
  • sandbox = relaxed
  • sandbox = true
• Tested, as applicable:
  • NixOS test(s) (look inside nixos/tests)
  • and/or package tests
  • or, for functions and "core" functionality, tests in lib/tests or pkgs/test
  • made sure NixOS tests are linked to the relevant packages
• Tested compilation of all packages that depend on this change using nix-shell -p nixpkgs-review --run "nixpkgs-review rev HEAD". Note: all changes have to be committed, also see nixpkgs-review usage
• Tested basic functionality of all binary files (usually in ./result/bin/)
• 24.11 Release Notes (or backporting 23.11 and 24.05 Release notes)
  • (Package updates) Added a release notes entry if the change is major or breaking
  • (Module updates) Added a release notes entry if the change is significant
  • (Module addition) Added a release notes entry if adding a new NixOS module
• Fits CONTRIBUTING.md.

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[Yarny0]

Review per https://github.com/NixOS/nixpkgs/blob/d95b1060ca298c62f56de90d0bf755c4c6b48e0a/nixos/README.md#module-updates

Reviewed points

• changes are backward compatible
• removed options are declared with mkRemovedOptionModule
• changes that are not backward compatible are documented in release notes
• module tests succeed on x86-64
• options types are appropriate
• options description is set
• options example is provided
• documentation affected by the changes is updated

Possible improvements

(none)

Comments

Thanks @lluchs for catching this -- apparently I didn't test all possible config value types in #253428 . Now I did, and I can confirm: After applying the pull request at hand, values with a list, true and null all yield what is expected.

I approve this pull request. I recommend it to be merged. I also suggest it to be backported to stable NixOS via the backport label: Given that the fixed bug blocks evaluation of the system configuration, it should not cause any regressions.

(Note: I'm the maintainer of the tsm-client module)

Result of nixpkgs-review run on x86_64-linux 1

1 package blacklisted:

• nixos-install-tools

[nixos-discourse]

This pull request has been mentioned on NixOS Discourse. There might be relevant details there:

https://discourse.nixos.org/t/prs-already-reviewed/2617/1834

[github-actions]

Successfully created backport PR for release-24.05:

• [Backport release-24.05] nixos/tsm-client: Fix multi-value dsm.sys options #328031