cmd/go: go list should set Package.Root to the module root directory, not GOPATH

[perillo]

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

$ go version
go version go1.16.4 linux/amd64

Does this issue reproduce with the latest release?

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

go env Output

$ go env
GO111MODULE="on"
GOARCH="amd64"
GOBIN="/home/manlio/.local/bin"
GOCACHE="/home/manlio/.cache/go-build"
GOENV="/home/manlio/.config/go/env"
GOEXE=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOINSECURE="*.local"
GOMODCACHE="/home/manlio/.local/lib/go/pkg/mod"
GONOPROXY=""
GONOSUMDB="*.local"
GOOS="linux"
GOPATH="/home/manlio/.local/lib/go:/home/manlio/src/go"
GOPRIVATE=""
GOPROXY="https://proxy.golang.org,direct"
GOROOT="/usr/lib/go"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/usr/lib/go/pkg/tool/linux_amd64"
GOVCS=""
GOVERSION="go1.16.4"
GCCGO="gccgo"
AR="ar"
CC="gcc"
CXX="g++"
CGO_ENABLED="1"
GOMOD="/home/manlio/src/go/src/github.com/perillo/i3workon/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-build2730267008=/tmp/go-build -gno-record-gcc-switches"
GOROOT/bin/go version: go version go1.16.4 linux/amd64
GOROOT/bin/go tool compile -V: compile version go1.16.4
uname -sr: Linux 5.12.2-arch1-1
/usr/lib/libc.so.6: GNU C Library (GNU libc) release release version 2.33.
gdb --version: GNU gdb (GDB) 10.2

What did you do?

From inside a module root directory:
go list -find -json ./pkg

What did you expect to see?

Package.Root set to the current module root directory, ignoring GOPATH.

What did you see instead?

Package.Root is set to the GOPATH directory containing the package.

[mvdan]

Can you run go env GOMOD right before or after go list, in the same directory? Because from your go env earlier it shows GOMOD="/dev/null", implying that you weren't inside a module.

[perillo]

Sorry, I ran the go bug command from a different directory. I have updated the information.

[mvdan]

On a module checked out at ~/src/sh, I correctly get "Root": "/home/mvdan/src/sh", for both go list -json . and go list -json -find .. My guess is that go list gets confused in your case, because you've checked out the module inside your GOPATH.

I still agree this sounds like a bug.

[perillo]

I have all my modules inside GOPATH and with Module.Dir = os.path.Join("$GOPATH/src", Module.Path).

[gopherbot]

Change https://golang.org/cl/319209 mentions this issue: cmd/go/internal/load: override Package.Root in module mode

[heschi]

cc @bcmills @jayconrod @matloob