feat: Adds a script to run apidiff

hack/apidiff.sh

@@ -0,0 +1,135 @@
+#!/usr/bin/env 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.
+
+# apidiff.sh: Compare public API changes between revisions or directories using Git worktrees.
+
+set -euo pipefail
+
+# Usage Information
+usage() {
+    echo "Usage: $0 [-r <revision>] [-t <revision>] [directory ...]"
+    echo "   -t <revision>: Report changes in code up to and including this revision."
+    echo "                  Default is the current working tree instead of a revision."
+    echo "   -r <revision>: Report changes in code added since this revision."
+    echo "                  Default is the common base of origin/master and HEAD."
+    exit 1
+}
+
+# Default Values
+TARGET_REVISION=""    # -t: Target revision
+REFERENCE_REVISION="" # -r: Reference revision
+TARGET_DIR="."        # Default directory to compare is current working directory
+API_DIFF_TOOL="apidiff"
+REF_API_SNAPSHOT="ref.api"
+TGT_API_SNAPSHOT="target.api"
+WORKTREES=()          # Track created worktrees for cleanup
+
+# Parse Command-Line Arguments
+while getopts ":t:r:" opt; do
+    case ${opt} in
+        t) TARGET_REVISION="$OPTARG" ;;
+        r) REFERENCE_REVISION="$OPTARG" ;;
+        \?) echo "Error: Invalid option -$OPTARG" >&2; usage ;;
+        :) echo "Error: Option -$OPTARG requires an argument." >&2; usage ;;
+    esac
+done
+shift $((OPTIND - 1))
+
+# Remaining arguments are directories
+if [ "$#" -ge 1 ]; then
+    TARGET_DIR="$1"
+fi
+
+# Check for apidiff tool, install it if not found
+if ! command -v "${API_DIFF_TOOL}" &> /dev/null; then
+    echo "Installing apidiff into ${GOBIN}."
+    go install golang.org/x/exp/cmd/apidiff@latest
+fi
+
+# Fetch common base if -r is not set
+if [ -z "${REFERENCE_REVISION}" ]; then
+    echo "Determining common base with origin/master..."
+    REFERENCE_REVISION=$(git merge-base origin/master HEAD)
+fi
+
+# Step 1: Create a temporary directory for worktrees
+TMP_DIR=$(mktemp -d)
+trap 'cleanup' EXIT
+
+cleanup() {
+    # Remove all created worktrees
+    for worktree in "${WORKTREES[@]}"; do
+        git worktree remove --force "$worktree"
+    done
+
+    # Remove temporary directory
+    rm -rf "${TMP_DIR}"
+}
+
+# Step 2: Export API snapshot for the reference revision
+REF_WORKTREE="${TMP_DIR}/ref"
+echo "Creating Git worktree for reference revision: ${REFERENCE_REVISION}"
+git worktree add "${REF_WORKTREE}" "${REFERENCE_REVISION}" --quiet
+WORKTREES+=("${REF_WORKTREE}")
+echo "Exporting API snapshot for reference revision..."
+pushd "${REF_WORKTREE}" > /dev/null
+"${API_DIFF_TOOL}" -m -w "${TMP_DIR}/${REF_API_SNAPSHOT}" "${TARGET_DIR}"
+popd > /dev/null
+
+# Step 3: Export API snapshot for the target revision
+TGT_WORKTREE="${TMP_DIR}/target"
+if [ -n "${TARGET_REVISION}" ]; then
+    echo "Creating Git worktree for target revision: ${TARGET_REVISION}"
+    git worktree add "${TGT_WORKTREE}" "${TARGET_REVISION}" --quiet
+    WORKTREES+=("${TGT_WORKTREE}")
+    TGT_PATH="${TGT_WORKTREE}"
+else
+    # If no target revision specified, compare with current working tree
+    TGT_PATH="${TARGET_DIR}"
+fi
+
+echo "Exporting API snapshot for target revision..."
+pushd "${TGT_PATH}" > /dev/null
+"${API_DIFF_TOOL}" -m -w "${TMP_DIR}/${TGT_API_SNAPSHOT}" "${TARGET_DIR}"
+popd > /dev/null
+
+# Step 4: Compare the two API snapshots for incompatible changes
+# Step 4: Compare the two API snapshots for changes
+echo "Checking for API changes..."
+# All changes
+all_changes=$("${API_DIFF_TOOL}" -m "${TMP_DIR}/${REF_API_SNAPSHOT}" "${TMP_DIR}/${TGT_API_SNAPSHOT}" 2>&1 | grep -v -e "^Ignoring internal package" || true)
+# Incompatible changes
+incompatible_changes=$("${API_DIFF_TOOL}" -incompatible -m "${TMP_DIR}/${REF_API_SNAPSHOT}" "${TMP_DIR}/${TGT_API_SNAPSHOT}" 2>&1 | grep -v -e "^Ignoring internal package" || true)
+
+# Print out results
+echo
+echo "API compatibility check completed."
+res=0
+if [ -n "$incompatible_changes" ]; then
+    res=1
+    echo "Incompatible API changes found!"
+else
+    echo "No incompatible API changes found."
+fi
+if [ -z "$all_changes" ]; then
+    echo "No API changes found."
+else
+    echo "All API changes:"
+    echo "$all_changes"
+    echo
+fi
+
+exit ${res}