yubikey-agent: fix on darwin

[philandstuff]

Mea culpa: in #92936, I did originally test on macOS but I forgot to
retest after adding the piv-go patch. Unfortunately, the piv-go patch
is broken on macOS (but fortunately it is unnecessary).

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.

[flokli]

Could you instead replace go-piv with go-piv/piv-go@8032767 (latest iteration of the PR? That should remove all sort of darwin-conditional code.

[philandstuff]

I tried writing postPatch = "go mod edit -replace=github.com/go-piv/piv-go=github.com/rawkode/piv-go@80327675dc86ebe3c494f9cd6fe5dee3eec5bf4c", which should work, but the go binary gets confused about where to put cache stuff, and the go-modules derivation didn't inherit the patch. There really ought to be a nicer way of inserting replace directives in buildGoModule than writing a patch file for go.mod 😞

[philandstuff]

@flokli @rawkode unfortunately the conditional is still needed. I tried compiling latest go-piv/piv-go#75 unconditionally on darwin and got:

@nix { "action": "setPhase", "phase": "unpackPhase" }
unpacking sources
unpacking source archive /nix/store/slyckbirmqymy0yj4cy27r21j8v2lmg8-source
source root is source
@nix { "action": "setPhase", "phase": "patchPhase" }
patching sources
applying patch /nix/store/ggq7300zpz3js06xyfq5hkfppq8zg9xd-use-piv-go-75.patch
patching file go.mod
patching file go.sum
@nix { "action": "setPhase", "phase": "configurePhase" }
configuring
@nix { "action": "setPhase", "phase": "buildPhase" }
building
Building subPackage ./.
github.com/go-piv/piv-go/piv
# pkg-config --cflags  -- libpcsclite
Package libpcsclite was not found in the pkg-config search path.
Perhaps you should add the directory containing `libpcsclite.pc'
to the PKG_CONFIG_PATH environment variable
No package 'libpcsclite' found
pkg-config: exit status 1

it looks like the pkg-config lines are not harmless on distros that don't support pkg-config 😞

[nixos-discourse]

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

https://discourse.nixos.org/t/using-go-mod-edit-in-packages/8305/1

[philandstuff]

@flokli @rawkode I've updated this PR to pull in the latest go-piv/piv-go#75, now that that has been fixed. This allowed me to remove the conditional. I've tested locally on NixOS and macOS and both compile successfully.

Please re-review.

[philandstuff]

urgh, my git fu is broken here :( seems I pushed a weird commit somehow which broke everything. Apologies for the mass notification 😞

I'll open a new PR once I've worked out what I'm doing again.