+sbt Validate mima on pull request

.github/workflows/binary-compatibility-checks.yml

@@ -0,0 +1,52 @@
+name: Binary Compatibility
+
+on:
+  pull_request:
+  push:
+    branches: [ main ]
+    tags-ignore: [ v* ]
+
+concurrency:
+  # Only run once for latest commit per ref and cancel other (previous) runs.
+  group: ci-${{ github.ref }}
+  cancel-in-progress: true
+
+permissions: { }
+
+jobs:
+  check-binary-compatibility:
+    name: Check / Binary Compatibility
+    runs-on: ubuntu-20.04
+    if: github.repository == 'apache/incubator-pekko-http'
+    strategy:
+      fail-fast: false
+      matrix:
+        SCALA_VERSION: [ 2.12, 2.13, 3.3 ]
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+          fetch-tags: 0
+
+      - name: Setup Java 11
+        uses: actions/setup-java@v3
+        with:
+          distribution: temurin
+          java-version: 11
+
+      - name: Cache Coursier cache
+        uses: coursier/cache-action@v6.4.0
+
+      - name: Enable jvm-opts
+        run: cp .jvmopts-ci .jvmopts
+
+      - name: Compile code
+        run: sbt ++${{ matrix.SCALA_VERSION }} Test/compile
+
+      - name: Report MiMa Binary Issues with Scala ${{ matrix.SCALA_VERSION }}
+        run: sbt -Dpekko.http.parallelExecution=false -Dpekko.test.timefactor=2 ++${{ matrix.SCALA_VERSION }} mimaReportBinaryIssues
+
+      - name: Check correct MiMa filter directories
+        run: |
+          sbt checkMimaFilterDirectories

project/MiMa.scala

@@ -20,10 +20,14 @@ import com.typesafe.tools.mima.plugin.MimaPlugin.autoImport._
 import scala.util.Try
 
 object MiMa extends AutoPlugin {
+  private val latestPatchOf10 = 0
 
   override def requires = MimaPlugin
   override def trigger = allRequirements
 
+  val checkMimaFilterDirectories =
+    taskKey[Unit]("Check that the mima directories are correct compared to latest version")
+
   override val projectSettings = Seq(
     mimaPreviousArtifacts := {
       val versions = Set("1.0.0")
@@ -48,7 +52,17 @@ object MiMa extends AutoPlugin {
       }
 
       Map.empty
-    })
+    },
+    checkMimaFilterDirectories := checkFilterDirectories(baseDirectory.value))
+
+  def checkFilterDirectories(moduleRoot: File): Unit = {
+    val nextVersionFilterDir =
+      moduleRoot / "src" / "main" / "mima-filters" / s"1.0.${latestPatchOf10 + 1}.backwards.excludes"
+    if (nextVersionFilterDir.exists()) {
+      throw new IllegalArgumentException(s"Incorrect mima filter directory exists: '$nextVersionFilterDir' " +
+        s"should be with number from current release '${moduleRoot / "src" / "main" / "mima-filters" / s"1.0.$latestPatchOf10.backwards.excludes"}")
+    }
+  }
 
   def latestForkVersion(fork: String, allVersions: Seq[String]): String =
     allVersions