env GOEXPERIMENT=golistexportnewformat

# "go list -export" should prefix paths for packages in GOROOT.
go list -export -json fmt
cp stdout out.json
go run q.go out.json Println
stdout '^\$GOROOT'

# "go list -export" should not prefix paths for packages not in GOROOT.
go list -export -json p.go
cp stdout out.json
go run q.go out.json V
! stdout '^\$GOROOT'

-- p.go --
package p

var V = 42

-- q.go --
package main

import (
	"encoding/json"
	"fmt"
	"go/importer"
	"go/token"
	"io"
	"log"
	"os"
)

func main() {
	data, err := os.ReadFile(os.Args[1])
	if err != nil {
		log.Fatal(err)
	}
	// This is a minimal output of go list -export -json.
	type output struct {
		ImportPath	string
		Export		string
	}
	var out output
	if err := json.Unmarshal(data, &out); err != nil {
		log.Fatal(err)
	}
	fset := token.NewFileSet()
	imp := importer.ForCompiler(fset, "gc", func(path string) (io.ReadCloser, error) {
		if path != out.ImportPath {
			log.Fatalf("unexpected import: %q", path)
		}
		return os.Open(out.Export)
	})
	pkg, err := imp.Import(out.ImportPath)
	if err != nil {
		log.Fatal(err)
	}
	fmt.Println(fset.Position(pkg.Scope().Lookup(os.Args[2]).Pos()).Filename)
}