goCmd := []string{goBinary, "list"}
	if noOpt {
		goCmd = append(goCmd, "-tags=noopt")
	}
	goCmd = appendCompilerFlags(goCmd)
	goCmd = append(goCmd, "-f={{if .Stale}}\tSTALE {{.ImportPath}}: {{.StaleReason}}{{end}}")

	out := runEnv(workdir, CheckExit, env, append(goCmd, targets...)...)
	if strings.Contains(out, "\tSTALE ") {
		os.Setenv("GODEBUG", "gocachehash=1")

		}
	}
}

// isStale reports whether pkg is stale, and why
func (tg *testgoData) isStale(pkg string) (bool, string) {
	tg.t.Helper()
	tg.run("list", "-f", "{{.Stale}}:{{.StaleReason}}", pkg)
	v := strings.TrimSpace(tg.getStdout())
	f := strings.SplitN(v, ":", 2)
	if len(f) == 2 {
		switch f[0] {
		case "true":
			return true, f[1]
		case "false":
			return false, f[1]
		}