env TESTGO_VERSION=go1.21
env GOTOOLCHAIN=local
! go mod download rsc.io/future@v1.0.0
stderr '^go: rsc.io/future@v1.0.0 requires go >= 1.999 \(running go 1.21; GOTOOLCHAIN=local\)$'

-- go.mod --
module m
go 1.21

-- x.go --
package p

	GOHOSTARCH
	GOHOSTOS
	GOINSECURE
	GOMIPS
	GOMIPS64
	GOMODCACHE
	GONOPROXY
	GONOSUMDB
	GOOS
	GOPATH
	GOPPC64
	GOPRIVATE
	GOPROXY
	GORISCV64
	GOROOT
	GOSUMDB
	GOTMPDIR
	GOTOOLCHAIN
	GOTOOLDIR
	GOVCS
	GOWASM
	GOWORK
	GO_EXTLINK_ENABLED
	PKG_CONFIG

  if [ "${GOTOOLCHAIN:-auto}" != 'auto' ]; then
    # no-op, just respect GOTOOLCHAIN
    :
  elif [ -n "${FORCE_HOST_GO:-}" ]; then
    # ensure existing host version is used, like before GOTOOLCHAIN existed
    export GOTOOLCHAIN='local'
  else
    # otherwise, we want to ensure the go version matches GO_VERSION
    GOTOOLCHAIN="go${GO_VERSION}"
    export GOTOOLCHAIN

//   - a binary distribution (tgz or zip) for the current GOOS and GOARCH
//   - a source distribution that is independent of GOOS/GOARCH
//   - the module mod, info, and zip files for a distribution in module form
//     (as used by GOTOOLCHAIN support in the go command).
//
// Distpack is typically invoked by the -distpack flag to make.bash.
// A cross-compiled distribution for goos/goarch can be built using:
//
//	GOOS=goos GOARCH=goarch ./make.bash -distpack

			if env[i].Value != "" {
				env[i].Changed = true
			}
		case "GOCACHE":
			env[i].Value, env[i].Changed = cache.DefaultDir()
		case "GOTOOLCHAIN":
			env[i].Value, env[i].Changed = cfg.EnvOrAndChanged("GOTOOLCHAIN", "")
		case "GODEBUG":
			env[i].Changed = env[i].Value != ""
		}
	}

	if work.GccgoBin != "" {

    --env "KUBE_STATIC_OVERRIDES=' ${KUBE_STATIC_OVERRIDES[*]:-} '"
    --env "FORCE_HOST_GO=${FORCE_HOST_GO:-}"
    --env "GO_VERSION=${GO_VERSION:-}"
    --env "GOTOOLCHAIN=${GOTOOLCHAIN:-}"
    --env "GOFLAGS=${GOFLAGS:-}"
    --env "GOGCFLAGS=${GOGCFLAGS:-}"
    --env "SOURCE_DATE_EPOCH=${SOURCE_DATE_EPOCH:-}"
  )

  # use GOLDFLAGS only if it is set explicitly.

		"GOSUMDB=" + testSumDBVerifierKey,
		"GONOPROXY=",
		"GONOSUMDB=",
		"GOVCS=*:all",
		"devnull=" + os.DevNull,
		"goversion=" + gover.Local(),
		"CMDGO_TEST_RUN_MAIN=true",
		"HGRCPATH=",
		"GOTOOLCHAIN=auto",
		"newline=\n",
	}

	if testenv.Builder() != "" || os.Getenv("GIT_TRACE_CURL") == "1" {
		// To help diagnose https://go.dev/issue/52545,
		// enable tracing for Git HTTPS requests.
		env = append(env,

	GOROOT
		The root of the go tree.
	GOSUMDB
		The name of checksum database to use and optionally its public key and
		URL. See https://golang.org/ref/mod#authenticating.
	GOTOOLCHAIN
		Controls which Go toolchain is used. See https://go.dev/doc/toolchain.
	GOTMPDIR
		The directory where the go command will write
		temporary source files, packages, and binaries.
	GOVCS

//	GOROOT
//		The root of the go tree.
//	GOSUMDB
//		The name of checksum database to use and optionally its public key and
//		URL. See https://golang.org/ref/mod#authenticating.
//	GOTOOLCHAIN
//		Controls which Go toolchain is used. See https://go.dev/doc/toolchain.
//	GOTMPDIR
//		The directory where the go command will write
//		temporary source files, packages, and binaries.
//	GOVCS

- Lower and upper case feature flag values are now allowed, but the name still has to match. ([#121441](https://github.com/kubernetes/kubernetes/pull/121441), [@soltysh](https://github.com/soltysh))
- Makefile and scripts now respect `GOTOOLCHAIN` and otherwise ensure `./.go-version` is used. ([#120279](https://github.com/kubernetes/kubernetes/pull/120279), [@BenTheElder](https://github.com/BenTheElder))