}

	t.Setenv("GO111MODULE", "on")
	t.Setenv("GOPATH", gopath)
	ctxt := Default
	ctxt.GOPATH = gopath
	ctxt.Dir = filepath.Join(gopath, "src/example.com/p")

	want := "go.mod file not found in current directory or any parent directory"
	if _, err := ctxt.Import("example.com/p", gopath, FindOnly); err == nil {
		t.Fatal("importing package when no go.mod is present succeeded unexpectedly")

export GO111MODULE ?= on
export GOPROXY ?= https://proxy.golang.org
export GOSUMDB ?= sum.golang.org

# If GOPATH is not set by the env, set it to a sane value
GOPATH ?= $(shell cd ${ISTIO_GO}/../../..; pwd)
export GOPATH

# If GOPATH is made up of several paths, use the first one for our targets in this Makefile
GO_TOP := $(shell echo ${GOPATH} | cut -d ':' -f1)
export GO_TOP

GO ?= go

GOARCH_LOCAL := $(TARGET_ARCH)

  #   * We could leave GOPATH alone and let `go install` write binaries
  #     wherever the user's GOPATH says (or doesn't say).
  #
  # Instead we set it to a phony local path and process the results ourselves.
  # In particular, GOPATH[0]/bin will be used for `go install`, with
  # cross-compiles adding an extra directory under that.
  export GOPATH="${KUBE_GOPATH}"

		// identity function for packages outside of the standard library.
		//
		// Part of the purpose of the vendor directory is to allow the packages in
		// the module to continue to build in GOPATH mode, and GOPATH-mode users
		// won't know about replacement aliasing. How important is it to maintain
		// compatibility?
		fmt.Fprintf(os.Stderr, "warning: %s imported as both %s and %s; making two copies.\n", realPath, realPath, pkg)

	// Override defaults computed in go/build with defaults
	// from go environment configuration file, if known.
	ctxt.GOPATH, GOPATHChanged = EnvOrAndChanged("GOPATH", gopath(ctxt))
	ctxt.GOOS = Goos
	ctxt.GOARCH = Goarch

	// Clear the GOEXPERIMENT-based tool tags, which we will recompute later.
	var save []string
	for _, tag := range ctxt.ToolTags {
		if !strings.HasPrefix(tag, "goexperiment.") {

	// of use-cases where -buildmode=shared still works today.
	// For now, run the tests in GOPATH mode only.
	os.Setenv("GO111MODULE", "off")

	// Some tests need to edit the source in GOPATH, so copy this directory to a
	// temporary directory and chdir to that.
	gopath := filepath.Join(workDir, "gopath")
	modRoot, err := cloneTestdataModule(gopath)
	if err != nil {
		return 0, err
	}
	if testing.Verbose() {

		base.Fatalf("go: 'go help work edit' accepts at most one argument")
	}
	var gowork string
	if len(args) == 1 {
		gowork = args[0]
	} else {
		modload.InitWorkfile()
		gowork = modload.WorkFilePath()
	}
	if gowork == "" {
		base.Fatalf("go: no go.work file found\n\t(run 'go work init' first or specify path using GOWORK environment variable)")
	}

	if *editGo != "" && *editGo != "none" {

	// GOROOT points at Go bootstrap GOROOT,
	// GOPATH points at our bootstrap workspace,
	// GOBIN is empty, so that binaries are installed to GOPATH/bin,
	// and GOOS, GOHOSTOS, GOARCH, and GOHOSTOS are empty,
	// so that Go bootstrap toolchain builds whatever kind of binary it knows how to build.
	// Restore GOROOT, GOPATH, and GOBIN when done.
	// Don't bother with GOOS, GOHOSTOS, GOARCH, and GOHOSTARCH,

// displayed when an error happens.
func Init(goPath string, goRoot string) {
	var goPathList []string
	var goRootList []string
	var defaultgoPathList []string
	var defaultgoRootList []string
	pathSeparator := ":"
	// Add all possible GOPATH paths into trimStrings
	// Split GOPATH depending on the OS type
	if runtime.GOOS == "windows" {
		pathSeparator = ";"
	}

stderr 'no modules specified'

# 'go mod download' should download exactly the requested module without dependencies.
rm -r $GOPATH/pkg/mod/cache/download/example.com
go mod download example.com/printversion@v1.0.0
exists $GOPATH/pkg/mod/cache/download/example.com/printversion/@v/v1.0.0.zip
! exists $GOPATH/pkg/mod/cache/download/example.com/version/@v/v1.0.0.zip

# 'go mod download all' should fail. "all" is not meaningful outside of a module.