chore: make apidiff focus on our APIs

We want to check if our public APIs have changed, not if our internal implementation has changed.

Focus only on differences in api/ and exp/api/

Author: justinsb

Makefile

@@ -103,10 +103,6 @@ SETUP_ENVTEST_VER := v0.0.0-20240522175850-2e9781e9fc60
 SETUP_ENVTEST_BIN := setup-envtest
 SETUP_ENVTEST := $(TOOLS_BIN_DIR)/$(SETUP_ENVTEST_BIN)
 
-GO_APIDIFF_VER := v0.8.3
-GO_APIDIFF_BIN := go-apidiff
-GO_APIDIFF := $(TOOLS_BIN_DIR)/$(GO_APIDIFF_BIN)
-
 GOTESTSUM_VER := v1.6.4
 GOTESTSUM_BIN := gotestsum
 GOTESTSUM := $(TOOLS_BIN_DIR)/$(GOTESTSUM_BIN)
@@ -260,9 +256,6 @@ $(CONVERSION_GEN): ## Build conversion-gen.
 $(RELEASE_NOTES): ## Build release notes.
 	GOBIN=$(TOOLS_BIN_DIR) $(GO_INSTALL) k8s.io/release/cmd/release-notes $(RELEASE_NOTES_BIN) $(RELEASE_NOTES_VER)
 
-$(GO_APIDIFF): ## Build go-apidiff from tools folder.
-	GOBIN=$(TOOLS_BIN_DIR) $(GO_INSTALL) github.com/joelanford/go-apidiff $(GO_APIDIFF_BIN) $(GO_APIDIFF_VER)
-
 $(CONVERSION_VERIFIER): go.mod
 	cd $(TOOLS_DIR); go build -tags=tools -o $@ sigs.k8s.io/cluster-api/hack/tools/conversion-verifier
 
@@ -282,9 +275,6 @@ $(KIND): ## Build kind into tools folder
 .PHONY: $(KUBECTL_BIN)
 $(KUBECTL_BIN): $(KUBECTL) ## Building kubectl from tools folder
 
-.PHONY: $(GO_APIDIFF_BIN)
-$(GO_APIDIFF_BIN): $(GO_APIDIFF)
-
 .PHONY: $(KIND_BIN)
 $(KIND_BIN): $(KIND) ## Building Kind from tools folder
 
@@ -576,13 +566,10 @@ clean-release: ## Remove the release folder
 	rm -rf $(RELEASE_DIR)
 
 .PHONY: apidiff
-apidiff: $(GO_APIDIFF) ## Check for API differences.
+apidiff: APIDIFF_OLD_COMMIT ?= $(shell git rev-parse origin/main)
+apidiff: $(GO_APIDIFF) ## Check for API differences
 	@$(call checkdiff) > /dev/null
-	@if ($(call checkdiff) | grep "api/"); then \
-		$(GO_APIDIFF) $(shell git rev-parse origin/main) --print-compatible; \
-	else \
-		echo "No changes to 'api/'. Nothing to do."; \
-	fi
+	APIDIFF_OLD_COMMIT=${APIDIFF_OLD_COMMIT} hack/verify-apidiff
 
 define checkdiff
 	git --no-pager diff --name-only FETCH_HEAD

hack/verify-apidiff

@@ -0,0 +1,41 @@
+#!/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.
+
+set -o errexit
+set -o nounset
+set -o pipefail
+
+REPO_ROOT=$(dirname "${BASH_SOURCE[0]}")/..
+cd "${REPO_ROOT}"
+
+if [[ -z "${APIDIFF_OLD_COMMIT:-}" ]]; then
+  APIDIFF_OLD_COMMIT=$(git rev-parse origin/main)
+fi
+
+
+echo "*** Running go-apidiff ***"
+
+# Run go-apidiff and filter for changes in api/ or exp/api/
+apidiffs=$(go run github.com/joelanford/[email protected] ${APIDIFF_OLD_COMMIT} || true)
+filtered=$(echo "$apidiffs" | grep -E 'cluster-api-provider-gcp/(api/|exp/api/)' || true)
+
+if [[ -n "$filtered" ]]; then
+  echo "API differences found in api/ or exp/api/:"
+  echo "$apidiffs"
+  exit 1
+else
+  echo "No differences found in api/ or exp/api/ packages"
+fi

scripts/ci-apidiff.sh

@@ -20,9 +20,6 @@ set -o pipefail
 
 REPO_ROOT=$(dirname "${BASH_SOURCE[0]}")/..
 
-APIDIFF="${REPO_ROOT}/hack/tools/bin/go-apidiff"
+cd "${REPO_ROOT}"
 
-cd "${REPO_ROOT}" && make "${APIDIFF##*/}"
-echo "*** Running go-apidiff ***"
-
-${APIDIFF} "${PULL_BASE_SHA}" --print-compatible
+APIDIFF_OLD_COMMIT="${PULL_BASE_SHA}" make apidiff