Incorrect goPackagePath for subdirectories

[oxzi]

While creating a deps.nix based on a go.mod with a dependency to github.com/ugorji/go/codec, the resulting goPackagePath was incorrect. The problem lies in the subdirectory-like path of this package. Your script parses the full package path (github.com/ugorji/go/codec) correctly and also extracts the correct URL (https://github.com/ugorji/go). However, this results to an entry where the goPackagePath (subdirectory) should fetch its parent folder as source. Therefore the compilation will fail. After changing the goPackagePath to its root (github.com/ugorji/go), everything worked smoothly.

Please excuse my confusing explanation. You can check out this small project of mine, where I came across this issue and modified the one line in deps.nix manually.

Now I'm kind of unsure how to solve this problem.

• A kind of stupid approach would be trimming the URL on its right side to a length of two directories. However, I don't think there is a specification saying that every project must lay at scheme://domain.tld/foo/bar.
• Another idea would be recreating the goPackagePath from the Package's URL field. On the other hand, I'm not sure if the URL must always represent the package path.

What are your thoughts about this? I would be happy to fix this, but would love to hear your thoughts first. Thanks for this nice project btw.

[adisbladis]

It turns out we already had this information (it was just discarded). The proper goPackagePath attribute is returned by https://godoc.org/golang.org/x/tools/go/vcs#RepoRootForImportPath.

[adisbladis]

Additionally I have added tests where one of the test cases is based on your report (https://github.com/adisbladis/vgo2nix/tree/master/tests/test_reporoot).

Thanks!

[martinetd]

I've just run into the same problem for https://github.com/ddvk/rmfakecloud

The generated deps.nix (as of master) contains:

  {
    goPackagePath = "github.com/dropbox/dropbox-sdk-go-unofficial/v6";
    fetch = {
      type = "git";
      url = "https://github.com/dropbox/dropbox-sdk-go-unofficial";
      rev = "v6.0.3";
      sha256 = "0wm50livb01i5qjpchknadc443vrpahvzyyn68w69dk4g3i2wcj9";
      moduleDir = "";
    };
  }

But the build fails unless I update goPackagePath to github.com/dropbox/dropbox-sdk-go-unofficial (without /v6 subdir) I honestly have no clue about go however so not sure where you're supposed to guess if we want a subdir or not... I see other sources have a subdir + moduleDir set, but that didn't work in this case.

Here's the error if this helps:

rmfakecloud> go/src/github.com/ddvk/rmfakecloud/internal/integrations/dropbox.go:8:2: cannot find package "github.com/dropbox/dropbox-sdk-go-unofficial/v6/dropbox" in any of:
rmfakecloud>    /nix/store/8jh9rqpmlyvfqmr71hll1a4a7wsqjnja-go-1.17.6/share/go/src/github.com/dropbox/dropbox-sdk-go-unofficial/v6/dropbox (from $GOROOT)
rmfakecloud>    /build/go/src/github.com/dropbox/dropbox-sdk-go-unofficial/v6/dropbox (from $GOPATH)
rmfakecloud> go/src/github.com/ddvk/rmfakecloud/internal/integrations/dropbox.go:9:2: cannot find package "github.com/dropbox/dropbox-sdk-go-unofficial/v6/dropbox/files" in any of:
rmfakecloud>    /nix/store/8jh9rqpmlyvfqmr71hll1a4a7wsqjnja-go-1.17.6/share/go/src/github.com/dropbox/dropbox-sdk-go-unofficial/v6/dropbox/files (from $GOROOT)
rmfakecloud>    /build/go/src/github.com/dropbox/dropbox-sdk-go-unofficial/v6/dropbox/files (from $GOPATH)

Inspecting manually, there is /build/go/src/github.com/dropbox/dropbox-sdk-go-unofficial/v6/v6/dropbox instead (note two /v6) which made me add a mv in preBuild first, but fixing the deps.nix makes more sense.

(full package here if that helps reproducing, with fixed deps.nix: http://cgit.notk.org/asmadeus/nixos-config.git/tree/pkgs/rmfakecloud/default.nix )

Thanks!