From dc6d8d4183472735149889984926d05279ac5e1e Mon Sep 17 00:00:00 2001
From: "opensearch-trigger-bot[bot]"
 <98922864+opensearch-trigger-bot[bot]@users.noreply.github.com>
Date: Tue, 2 Apr 2024 09:00:59 -0400
Subject: [PATCH] Detect breaking changes on pull requests (#12974) (#13010)

(cherry picked from commit 2dc071ff2546b0c6483b9e0a382badf9ac353cdc)
Signed-off-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>

Signed-off-by: Peter Nied <petern@amazon.com>
Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>
Co-authored-by: Peter Nied <petern@amazon.com>
---
 .github/workflows/detect-breaking-change.yml | 24 ++++++
 CHANGELOG.md                                 |  1 +
 server/build.gradle                          | 79 ++++++++++++++++++++
 3 files changed, 104 insertions(+)
 create mode 100644 .github/workflows/detect-breaking-change.yml

diff --git a/.github/workflows/detect-breaking-change.yml b/.github/workflows/detect-breaking-change.yml
new file mode 100644
index 0000000000000..fec605c58f9c7
--- /dev/null
+++ b/.github/workflows/detect-breaking-change.yml
@@ -0,0 +1,24 @@
+name: "Detect Breaking Changes"
+on: [push, pull_request]
+jobs:
+  detect-breaking-change:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v4
+    - uses: actions/setup-java@v4
+      with:
+        distribution: temurin # Temurin is a distribution of adoptium
+        java-version: 21
+    - uses: gradle/gradle-build-action@v3
+      with:
+        arguments: japicmp
+        gradle-version: 8.7
+        build-root-directory: server
+    - if: failure()
+      run: cat server/build/reports/java-compatibility/report.txt
+    - if: failure()
+      uses: actions/upload-artifact@v4
+      with:
+        name: java-compatibility-report.html
+        path: ${{ github.workspace }}/server/build/reports/java-compatibility/report.html
+  
\ No newline at end of file
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 67f1c63f5f81d..5fd86c76fe6ab 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -11,6 +11,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 - Allow setting KEYSTORE_PASSWORD through env variable ([#12865](https://github.com/opensearch-project/OpenSearch/pull/12865))
 - Add a counter to node stat (and _cat/shards) api to track shard going from idle to non-idle ([#12768](https://github.com/opensearch-project/OpenSearch/pull/12768))
 - [Concurrent Segment Search] Disable concurrent segment search for system indices and throttled requests ([#12954](https://github.com/opensearch-project/OpenSearch/pull/12954))
+- Detect breaking changes on pull requests ([#9044](https://github.com/opensearch-project/OpenSearch/pull/9044))
 - Add cluster primary balance contraint for rebalancing with buffer ([#12656](https://github.com/opensearch-project/OpenSearch/pull/12656))
 
 ### Dependencies
diff --git a/server/build.gradle b/server/build.gradle
index a10d010c07b00..abfa53315b307 100644
--- a/server/build.gradle
+++ b/server/build.gradle
@@ -36,6 +36,7 @@ plugins {
   id('opensearch.publish')
   id('opensearch.internal-cluster-test')
   id('opensearch.optional-dependencies')
+  id('me.champeau.gradle.japicmp') version '0.4.2'
 }
 
 publishing {
@@ -414,3 +415,81 @@ tasks.named("sourcesJar").configure {
     duplicatesStrategy = DuplicatesStrategy.EXCLUDE
   }
 }
+
+/** Compares the current build against a snapshot build */
+tasks.register("japicmp", me.champeau.gradle.japicmp.JapicmpTask) {
+    oldClasspath.from(files("${buildDir}/snapshot/opensearch-${version}.jar"))
+    newClasspath.from(tasks.named('jar'))
+    onlyModified = true
+    failOnModification = true
+    ignoreMissingClasses = true
+    annotationIncludes = ['@org.opensearch.common.annotation.PublicApi']
+    txtOutputFile = layout.buildDirectory.file("reports/java-compatibility/report.txt")
+    htmlOutputFile = layout.buildDirectory.file("reports/java-compatibility/report.html")
+    dependsOn downloadSnapshot
+}
+
+/** If the Java API Comparison task failed, print a hint if the change should be merged from its target branch */
+gradle.taskGraph.afterTask { Task task, TaskState state ->
+    if (task.name == 'japicmp' && state.failure != null) {
+        def sha = getGitShaFromJar("${buildDir}/snapshot/opensearch-${version}.jar")
+        logger.info("Incompatiable java api from snapshot jar built off of commit ${sha}")
+
+        if (!inHistory(sha)) {
+          logger.warn('\u001B[33mPlease merge from the target branch and run this task again.\u001B[0m')
+        }
+    }
+}
+
+/** Downloads latest snapshot from maven repository */
+tasks.register("downloadSnapshot", Copy) {
+    def mavenSnapshotRepoUrl = "https://aws.oss.sonatype.org/content/repositories/snapshots/"
+    def groupId = "org.opensearch"
+    def artifactId = "opensearch"
+
+    repositories {
+        maven {
+            url mavenSnapshotRepoUrl
+        }
+    }
+
+    configurations {
+        snapshotArtifact
+    }
+
+    dependencies {
+        snapshotArtifact("${groupId}:${artifactId}:${version}:")
+    }
+
+    from configurations.snapshotArtifact
+    into "$buildDir/snapshot"
+}
+
+/** Check if the sha is in the current history */
+def inHistory(String sha) {
+    try {
+      def commandCheckSha = "git merge-base --is-ancestor ${sha} HEAD"
+      commandCheckSha.execute()
+      return true
+    } catch (Exception) {
+      return false
+    }
+}
+
+/** Extracts the Git SHA used to build a jar from its manifest */
+def getGitShaFromJar(String jarPath) {
+    def sha = ''
+    try {
+        // Open the JAR file
+        def jarFile = new java.util.jar.JarFile(jarPath)
+        // Get the manifest from the JAR file
+        def manifest = jarFile.manifest
+        def attributes = manifest.mainAttributes
+        // Assuming the Git SHA is stored under an attribute named 'Git-SHA'
+        sha = attributes.getValue('Change')
+        jarFile.close()
+    } catch (IOException e) {
+        println "Failed to read the JAR file: $e.message"
+    }
+    return sha
+}