@bjornfor @rvolosatovs @zimbatm you maintain go packages, can you explain what's the error here telling me, please?

Where's the error? I don't think I maintain any go package, but I'm interested in learning how to (package golang projects with Nix).

The error is:

$ nix-build -A pms
these derivations will be built:
  /nix/store/c03q6swidr4ziqib3z4vhkzs6g23amc1-pms-0.42-go-modules.drv
  /nix/store/fk0dpczhf39qkz13x5y4a2qsih8h7n38-pms-0.42.drv
building '/nix/store/c03q6swidr4ziqib3z4vhkzs6g23amc1-pms-0.42-go-modules.drv'...
unpacking sources
unpacking source archive /nix/store/vmw9qfadynclkyfjihvrb5xizimp2qj0-source
source root is source
patching sources
configuring
building
go mod download: no modules specified (see 'go help mod download')
builder for '/nix/store/c03q6swidr4ziqib3z4vhkzs6g23amc1-pms-0.42-go-modules.drv' failed with exit code 1
cannot build derivation '/nix/store/fk0dpczhf39qkz13x5y4a2qsih8h7n38-pms-0.42.drv': 1 dependencies couldn't be built
error: build of '/nix/store/fk0dpczhf39qkz13x5y4a2qsih8h7n38-pms-0.42.drv' failed

Well, at least on my machine?

So this is a step forward, but the result is empty after this...

Someone with go experience please!

I'd suggest you:

1. clone the upstream repository
2. checkout the required version(0.42)
3. run go mod download in the repository
4. check in all modified/created files (most probably only created go.sum)
5. create a patch containing all changes - e.g. git show > go-modules.patch on Linux - note that example may lack newline at the end of file
6. move the patch from 5. to directory containing this package
7. change buildGoPackage to buildGoModule
8. remove goDeps and goPackagePath
9. add patches attr containing the filename of patch from 5. For example:

{
	# other attrs ...
	patches = [
		go-modules.patch
	];
}

Preferrably file a PR upstream with changes from 5., most importantly containing go.sum

go mod download does not create any files in the repository for me.

There's no go.sum?
That's weird.
You can also try go mod init and/or go mod vendor, but I'm quite sure go.sum should have been created.

Are you using the latest master commit? Do you see go.mod present(I see it's there on master https://github.com/ambientsound/pms/blob/master/go.mod)?

If you're using 0.42, then it will not work, because that is not even a Go project. It's seems that tagged commit is from 2010, so not sure we should merge that in the first place.

What I would suggest is to use master directly and follow the steps in #76188 (comment). AFAIK the naming convention for such cases is to name the package X-unstable, i.e. pms-unstable in this case.

Too much hassle for me, sorry.