cmd/go: no Module information in list -e output after any error loading package

[myitcv]

What version of Go are you using (go version)?

$ go version
go version devel +0cb3415154 Tue Feb 16 02:07:02 2021 +0000 linux/amd64

Does this issue reproduce with the latest release?

Yes

What operating system and processor architecture are you using (go env)?

go env Output

$ go env
GO111MODULE=""
GOARCH="amd64"
GOBIN=""
GOCACHE="/home/myitcv/.cache/go-build"
GOENV="/home/myitcv/.config/go/env"
GOEXE=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOINSECURE=""
GOMODCACHE="/home/myitcv/gostuff/pkg/mod"
GONOPROXY=""
GONOSUMDB=""
GOOS="linux"
GOPATH="/home/myitcv/gostuff"
GOPRIVATE=""
GOPROXY="https://proxy.golang.org,direct"
GOROOT="/home/myitcv/gos"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/home/myitcv/gos/pkg/tool/linux_amd64"
GOVCS=""
GOVERSION="devel +0cb3415154 Tue Feb 16 02:07:02 2021 +0000"
GCCGO="gccgo"
AR="ar"
CC="gcc"
CXX="g++"
CGO_ENABLED="1"
GOMOD="/tmp/tmp.MFFZzggPNu/go.mod"
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
PKG_CONFIG="pkg-config"
GOGCCFLAGS="-fPIC -m64 -pthread -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build741706514=/tmp/go-build -gno-record-gcc-switches"

What did you do?

go list -e -f {{.Module}}

-- blah.go --
package blah

import _ "embed"

//go:embed README.md
var readme string
-- go.mod --
module mod.com

go 1.16

What did you expect to see?

mod.com

What did you see instead?

<nil>

This has implications for users of go list, i.e. go/packages.

[jayconrod]

In cmd/go/internal/load.Package.load, it looks like we don't populate the Module field if there was any error loading the package. For example, if a blah.c file is present but the package doesn't use cgo or swig, the Error field is populated but the Module field is not.

I don't think anything prevents us from populated the Module field here.

[sidntrivedi012]

Hey @jayconrod , I would like to help out to fix this issue. How should I proceed? Thanks :)

[jayconrod]

@sidntrivedi012 Your help is most welcome.

I think this can be fixed in pkg.go by moving this block up to right after we push the import path on the stack.

Please make sure to add a regression test in src/cmd/go/testdata/script. There's a README there that explains the format.

[supriya-premkumar]

I can take this one up if this in the backlog. @jayconrod Please feel free to assign this one to me. 🙏🏽

[sidntrivedi012]

Hey @supriya-premkumar , I got somewhat stuck in the weekdays so couldn't get the bandwidth to work on it.

I am planning to write a patch for it in this weekend. Will surely comment here to assign it to you if I fail to triage it.

Thanks 😃

[supriya-premkumar]

Hey @supriya-premkumar , I got somewhat stuck in the weekdays so couldn't get the bandwidth to work on it.

I am planning to write a patch for it in this weekend. Will surely comment here to assign it to you if I fail to triage it.

Thanks 😃

No worries at all. Go for it!