ci: Use Linkage Checker to test Binary Compatibility

Author: lqiu96

.github/workflows/downstream_protobuf_compatibility_check_nightly.yaml

@@ -52,3 +52,6 @@ jobs:
         run: echo "Testing with Protobuf-Java v${{ matrix.protobuf-version }}"
       - name: Perform downstream source compatibility testing
         run: REPOS_UNDER_TEST="${{ matrix.repo }}" PROTOBUF_RUNTIME_VERSION="${{ matrix.protobuf-version}}" ./.kokoro/nightly/downstream-protobuf-source-compatibility.sh
+      - name: Perform downstream binary compatibility testing
+        run: REPOS_UNDER_TEST="${{ matrix.repo }}" PROTOBUF_RUNTIME_VERSION="${{ matrix.protobuf-version}}" ./.kokoro/nightly/downstream-protobuf-binary-compatibility.sh
+

.kokoro/nightly/downstream-protobuf-binary-compatibility.sh

@@ -0,0 +1,59 @@
+#!/bin/bash
+# Copyright 2024 Google LLC
+#
+# 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 -eo pipefail
+
+# Comma-delimited list of repos to test with the local java-shared-dependencies
+if [ -z "${REPOS_UNDER_TEST}" ]; then
+  echo "REPOS_UNDER_TEST must be set to run downstream-protobuf-source-compatibility.sh"
+  echo "Expects a comma-delimited list: i.e REPOS_UNDER_TEST=\"java-bigtable,java-bigquery\""
+  exit 1
+fi
+
+# Version of Protobuf-Java runtime to compile with
+if [ -z "${PROTOBUF_RUNTIME_VERSION}" ]; then
+  echo "PROTOBUF_RUNTIME_VERSION must be set to run downstream-protobuf-source-compatibility.sh"
+  echo "Expects a single Protobuf-Java runtime version i.e. PROTOBUF_RUNTIME_VERSION=\"4.28.3\""
+  exit 1
+fi
+
+git clone https://github.com/lqiu96/cloud-opensource-java.git
+pushd cloud-opensource-java
+mvn -B -ntp clean compile
+pushd dependencies
+
+for repo in ${REPOS_UNDER_TEST//,/ }; do # Split on comma
+  repo_name=$(echo "$repo" | cut -d '-' -f 2-)
+  # Perform source-compatibility testing on main (latest changes)
+  git clone "https://github.com/googleapis/$repo.git" --depth=1
+  pushd "$repo"
+
+  mvn clean install -T 1C -DskipTests
+
+  # For google-cloud-java monorepo, use the parent google-cloud-java version.
+  # Otherwise, use the first google-cloud-* artifact's version.
+  if [[ "$repo" == "google-cloud-java" ]]; then
+    primary_artifact=$(grep -E "^${repo}" "versions.txt" | head -n 1)
+  else
+    primary_artifact=$(grep -E "^google-cloud-${repo_name}" "versions.txt" | head -n 1)
+  fi
+  echo "${primary_artifact}"
+  version=$(echo "${primary_artifact}" | tr ':' '\n' | tail -n 1)
+  echo "${version}"
+
+  mvn -B -ntp exec:java -Dexec.mainClass="com.google.cloud.tools.opensource.classpath.LinkageCheckerMain" -Dexec.args="-r --artifacts com.google.cloud:google-cloud-${repo_name}:${version}"
+  popd
+done
+popd