Add script to verify dependencies

Makefile

@@ -281,8 +281,15 @@ clean:
 	rm -rf output/
 	rm -f coverage.out
 
-depup:
-	go get $(shell go list -f '{{if not (or .Main .Indirect)}}{{.Path}}{{end}}' -mod=mod -m all)
+.PHONY: gomod
+gomod:
 	go mod tidy
 	go mod vendor
 	cd test; go mod tidy
+
+.PHONY: goget
+goget:
+	go get $(shell go list -f '{{if not (or .Main .Indirect)}}{{.Path}}{{end}}' -mod=mod -m all)
+
+.PHONY: depup
+depup: goget gomod

hack/verify-gomod.sh

@@ -0,0 +1,30 @@
+#!/bin/bash
+
+# Copyright 2024 The Kubernetes Authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+set -o errexit
+set -o nounset
+set -o pipefail
+
+make gomod
+changes=$(git status --porcelain go.mod go.sum vendor/ tests/e2e/go.mod  tests/e2e/go.sum || true)
+if [ -n "${changes}" ]; then
+  echo "ERROR: go modules are not up to date; please run: make gomod"
+  echo "changed files:"
+  printf "%s" "${changes}\n"
+  echo "git diff:"
+  git --no-pager diff
+  exit 1
+fi