}
		if v, ok := rawGoVersion.Load(m); ok {
			info.GoVersion = v.(string)
		} else {
			panic("internal error: GoVersion not set for main module")
		}
		if modRoot := MainModules.ModRoot(m); modRoot != "" {
			info.Dir = modRoot
			info.GoMod = modFilePath(modRoot)
		}
		return info
	}

	info := &modinfo.ModulePublic{
		Path:     m.Path,
		Version:  m.Version,
		Indirect: rs != nil && !rs.direct[m.Path],

func cloneTestdataModule(gopath string) (string, error) {
	modRoot := filepath.Join(gopath, "src", "testshared")
	if err := cgotest.OverlayDir(modRoot, "testdata"); err != nil {
		return "", err
	}
	if err := os.WriteFile(filepath.Join(modRoot, "go.mod"), []byte("module testshared\n"), 0644); err != nil {
		return "", err
	}
	return modRoot, nil
}

		log.Fatal(err)
	}

	if os.Getenv("GO111MODULE") == "on" {
		out, err := exec.Command("go", "env", "GOMOD").Output()
		if err != nil {
			log.Fatal(err)
		}
		modRoot := filepath.Dir(strings.TrimSpace(string(out)))
		check(data, "module root", modRoot)
	} else {
		check(data, "GOPATH", os.Getenv("GOPATH"))
	}
	check(data, "GOROOT", os.Getenv("GOROOT"))
}

func check(data []byte, desc, dir string) {

		log.Panic(err)
	}
	defer os.RemoveAll(GOPATH)
	os.Setenv("GOPATH", GOPATH)

	modRoot := filepath.Join(GOPATH, "src", "testcshared")
	if err := cgotest.OverlayDir(modRoot, "testdata"); err != nil {
		log.Panic(err)
	}
	if err := os.Chdir(modRoot); err != nil {
		log.Panic(err)
	}
	os.Setenv("PWD", modRoot)
	if err := os.WriteFile("go.mod", []byte("module testcshared\n"), 0666); err != nil {
		log.Panic(err)

	// Copy testdata into GOPATH/src/testarchive, along with a go.mod file
	// declaring the same path.
	modRoot := filepath.Join(GOPATH, "src", "testcarchive")
	if err := cgotest.OverlayDir(modRoot, "testdata"); err != nil {
		log.Panic(err)
	}
	if err := os.Chdir(modRoot); err != nil {
		log.Panic(err)
	}
	os.Setenv("PWD", modRoot)
	if err := os.WriteFile("go.mod", []byte("module testcarchive\n"), 0666); err != nil {
		log.Panic(err)
	}

			}
			modroot := modload.PackageModRoot(ctx, r.path)
			if modroot == "" && str.HasPathPrefix(r.dir, cfg.GOROOTsrc) {
				modroot = cfg.GOROOTsrc
				gorootSrcCmd := filepath.Join(cfg.GOROOTsrc, "cmd")
				if str.HasPathPrefix(r.dir, gorootSrcCmd) {
					modroot = gorootSrcCmd
				}
			}
			if modroot != "" {
				if rp, err := modindex.GetPackage(modroot, r.dir); err == nil {