caddy: withPlugins better error messages for untagged plugins

[stepbrobd]

Things done

Context:
#358586 (comment)
#358586 (comment)

Continuation of #358586, better error messages for untagged plugins

When using pkgs.caddy.withPlugins, if a plugin is untagged upstream, users usually provide a commit SHA to replace to the tag/version. This will result in installCheckPhase failure as caddy build-info output uses pseudo-version number (e.g. v0.0.0-20170915032832-14c0d48ead0c).

Example error:

$ nom-build --expr 'with import ./. { }; caddy.withPlugins { plugins = [ "github.com/caddy-dns/[email protected]" "github.com/caddy-dns/cloudflare@89f16b99c18e" "github.com/mholt/caddy-webdav@42168ba04c9dc2cd228ab8c453dbab27654e52e6" ]; hash = "sha256-wqXSd1Ep9TVpQi570TTb96LwzNYvWL5EBJXMJfYWCAk="; }'
...
> Running phase: installCheckPhase
> Plugins not found: github.com/caddy-dns/cloudflare@89f16b99c18e
> Plugins not found: github.com/mholt/caddy-webdav@42168ba04c9dc2cd228ab8c453dbab27654e52e6
...

The error output will change to the following:

$ nom-build --expr 'with import ./. { }; caddy.withPlugins { plugins = [ "github.com/caddy-dns/[email protected]" "github.com/caddy-dns/cloudflare@89f16b99c18e" "github.com/mholt/caddy-webdav@42168ba04c9dc2cd228ab8c453dbab27654e52e6" ]; hash = "sha256-wqXSd1Ep9TVpQi570TTb96LwzNYvWL5EBJXMJfYWCAk="; }'
...
> Running phase: installCheckPhase
> Plugin "github.com/caddy-dns/cloudflare" have incorrect tag:
>   specified: "github.com/caddy-dns/cloudflare@89f16b99c18e"
>   got: "github.com/caddy-dns/[email protected]"
> Plugin "github.com/mholt/caddy-webdav" have incorrect tag:
>   specified: "github.com/mholt/caddy-webdav@42168ba04c9dc2cd228ab8c453dbab27654e52e6"
>   got: "github.com/mholt/[email protected]"
...

• 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/)
• 25.05 Release Notes (or backporting 24.11 and 25.05 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.

---

Add a 👍 reaction to pull requests you find important.

[vincentbernat]

Does not display anything if a plugin is not found at all.

[stepbrobd]

Added a fall back but I don't think this will ever get triggered unless there's smth wrong with xcaddy

[nixos-discourse]

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

https://discourse.nixos.org/t/prs-ready-for-review/3032/5021

[vincentbernat]

Out of curiosity, is that a best practice? Is it explained somewhere?

[thiagokokada]

Neither. I particularly don't like but it doesn't hurt (as long you're not using with lib).

[stepbrobd]

I've seen a few modules (in nixpkgs of course) pull in library functions right after getting arguments like these:

• nixpkgs/nixos/modules/services/monitoring/metricbeat.nix

  Lines 8 to 17 in 821e42c

  	let
  	inherit (lib)
  	attrValues
  	literalExpression
  	mkEnableOption
  	mkPackageOption
  	mkIf
  	mkOption
  	types
  	;

• nixpkgs/nixos/modules/services/networking/mtr-exporter.nix

  Lines 8 to 23 in 4506ece

  	let
  	inherit (lib)
  	maintainers
  	types
  	literalExpression
  	escapeShellArg
  	escapeShellArgs
  	mkEnableOption
  	mkOption
  	mkRemovedOptionModule
  	mkIf
  	mkPackageOption
  	optionalString
  	concatMapStrings
  	concatStringsSep
  	;

• nixpkgs/nixos/modules/services/networking/ergo.nix

  Lines 13 to 20 in 4506ece

  	inherit (lib)
  	literalExpression
  	mkEnableOption
  	mkIf
  	mkOption
  	optionalString
  	types
  	;

  
  And I've taken quite a liking to this style, so yeah... Not sure if this is the "best practice" tho