Add verify script to detect dead code

Author: adrianmoisey

hack/verify-vpa-flags.sh renamed to hack/verify-vpa.sh

@@ -19,7 +19,9 @@ set -o nounset
 set -o pipefail
 
 KUBE_ROOT=$(dirname "${BASH_SOURCE}")/..
-VPA_FLAGS_SCRIPT="${KUBE_ROOT}/vertical-pod-autoscaler/hack/verify-vpa-flags.sh"
+VPA_VERIFY_SCRIPTS="${KUBE_ROOT}/vertical-pod-autoscaler/hack/verify-*.sh"
 
-echo "Running VPA flags verification..."
-"$VPA_FLAGS_SCRIPT"
+for script in $VPA_VERIFY_SCRIPTS; do
+  echo "Running VPA verification script ${script}..."
+  "${script}"
+done

vertical-pod-autoscaler/hack/update-codegen.sh

@@ -20,9 +20,11 @@ set -o pipefail
 
 GO_CMD=${1:-go}
 CURRENT_DIR=$(dirname "${BASH_SOURCE[0]}")
-REPO_ROOT="$(git rev-parse --show-toplevel)"
-CODEGEN_PKG=$($GO_CMD list -m -mod=readonly -f "{{.Dir}}" k8s.io/code-generator)
 cd "${CURRENT_DIR}/.."
+go mod download
+CODEGEN_PKG=$($GO_CMD list -m -mod=readonly -f "{{.Dir}}" k8s.io/code-generator)
+
+REPO_ROOT="$(git rev-parse --show-toplevel)"
 
 # shellcheck source=/dev/null
 source "${CODEGEN_PKG}/kube_codegen.sh"

vertical-pod-autoscaler/hack/verify-deadcode-elimination.sh

@@ -0,0 +1,61 @@
+#!/usr/bin/env bash
+
+# Copyright 2025 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.
+
+# This script verifies if the golang linker is eliminating dead code in
+# various components we care about, such as kube-apiserver, kubelet and others
+# Usage: `hack/verify-deadcode-elimination.sh`.
+
+set -o errexit
+set -o nounset
+set -o pipefail
+
+SCRIPT_ROOT=$(dirname "${BASH_SOURCE[0]}")/..
+cd "${SCRIPT_ROOT}"
+COMPONENTS=("admission-controller" "recommender" "updater")
+FAILED=false
+
+# Install whydeadcode
+go install github.com/aarzilli/whydeadcode@latest
+
+# Prefer full path for running zeitgeist
+WHYDEADCODE_BIN="$(which whydeadcode)"
+
+for binary in "${COMPONENTS[@]}"; do
+  echo "Processing ${binary} ..."
+  pushd "pkg/${binary}"
+  output=$(GOLDFLAGS=-dumpdep go build -ldflags=-dumpdep -o "${binary}" 2>&1 | grep "\->" | ${WHYDEADCODE_BIN} 2>&1)
+  if [[ -n "$output" ]]; then
+    echo "golang linker is not eliminating dead code in ${binary}, please check the trace output below:"
+    echo "(NOTE: that there may be false positives, but the first trace should be a real issue)"
+    echo "$output"
+    FAILED=true
+    FAILED_BINARIES+=("${binary}")
+  fi
+
+  # Find the binary and print its size
+  echo "Finding ${binary} binary and checking its size:"
+    ls -altrh "${binary}"
+  echo ""
+  popd
+done
+
+if [[ "$FAILED" == "true" ]]; then
+  echo "Dead code elimination check failed for the following binaries:"
+  for failed_binary in "${FAILED_BINARIES[@]}"; do
+    echo "  - ${failed_binary}"
+  done
+  exit 1
+fi