From d1b5a9953a0b80cc449fbdbcaebe07ff9d948f53 Mon Sep 17 00:00:00 2001
From: Benjamin Elder <bentheelder@google.com>
Date: Wed, 30 Aug 2023 13:42:54 -0700
Subject: [PATCH 1/2] handle GOTOOLCHAIN in kube::golang::verify_go_version

for now:
- shim FORCE_HOST_GO to GOTOOLCHAIN=local
- treat GOTOOLCHAIN set and !=auto like FORCE_HOST_GO
- otherwise set GOTOOLCHAIN=go${GO_VERSION} and fallback to gimme if necessary

TODO: set toolchain statements in go.mod files and keep them in sync
---
 hack/lib/golang.sh | 16 +++++++++++++---
 1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/hack/lib/golang.sh b/hack/lib/golang.sh
index 983ff368e25..4284eb5bae3 100755
--- a/hack/lib/golang.sh
+++ b/hack/lib/golang.sh
@@ -466,13 +466,23 @@ kube::golang::create_gopath_tree() {
 kube::golang::verify_go_version() {
   # default GO_VERSION to content of .go-version
   GO_VERSION="${GO_VERSION:-"$(cat "${KUBE_ROOT}/.go-version")"}"
-  # only setup go if we haven't set FORCE_HOST_GO, or `go version` doesn't match GO_VERSION
-  if ! ([ -n "${FORCE_HOST_GO:-}" ] || \
-      (command -v go >/dev/null && [ "$(go version | cut -d' ' -f3)" = "go${GO_VERSION}" ])); then
+  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${GO_VERSION}"
+    export GOTOOLCHAIN
+    # if go is either not installed or too old to respect GOTOOLCHAIN then use gimme
+    if ! (command -v go >/dev/null && [ "$(go version | cut -d' ' -f3)" = "${GOTOOLCHAIN}" ]); then
       export GIMME_ENV_PREFIX=${GIMME_ENV_PREFIX:-"${KUBE_OUTPUT}/.gimme/envs"}
       export GIMME_VERSION_PREFIX=${GIMME_VERSION_PREFIX:-"${KUBE_OUTPUT}/.gimme/versions"}
       # eval because the output of this is shell to set PATH etc.
       eval "$("${KUBE_ROOT}/third_party/gimme/gimme" "${GO_VERSION}")"
+    fi
   fi
 
   if [[ -z "$(command -v go)" ]]; then

From d765e40a98870aa2b5280c701fffaaac61b4dfe7 Mon Sep 17 00:00:00 2001
From: Benjamin Elder <bentheelder@google.com>
Date: Mon, 11 Sep 2023 14:20:19 -0700
Subject: [PATCH 2/2] pass GOTOOLCHAIN to build containers

---
 build/common.sh | 1 +
 1 file changed, 1 insertion(+)

diff --git a/build/common.sh b/build/common.sh
index 4eb7f541c1d..b011fbf6fb5 100755
--- a/build/common.sh
+++ b/build/common.sh
@@ -540,6 +540,7 @@ function kube::build::run_build_command_ex() {
     --env "KUBE_CGO_OVERRIDES=' ${KUBE_CGO_OVERRIDES[*]:-} '"
     --env "FORCE_HOST_GO=${FORCE_HOST_GO:-}"
     --env "GO_VERSION=${GO_VERSION:-}"
+    --env "GOTOOLCHAIN=${GOTOOLCHAIN:-}"
     --env "GOFLAGS=${GOFLAGS:-}"
     --env "GOGCFLAGS=${GOGCFLAGS:-}"
     --env "SOURCE_DATE_EPOCH=${SOURCE_DATE_EPOCH:-}"