Check binary compatibility with MiMa

.github/workflows/ci.yml

@@ -43,6 +43,23 @@ jobs:
       - name: Run unit tests
         run: sbt testUnit
 
+  mima:
+    runs-on: ubuntu-24.04
+    steps:
+      - name: Checkout current branch
+        uses: actions/checkout@v6
+        with:
+          fetch-depth: 0
+      - name: Setup Scala and Java
+        uses: coursier/setup-action@v3
+        with:
+          jvm: temurin:25
+          apps: sbt
+      - name: Cache scala dependencies
+        uses: coursier/cache-action@v8
+      - name: Check binary compatibility
+        run: sbt mima
+
   docs:
     runs-on: ubuntu-24.04
     steps:
@@ -111,7 +128,7 @@ jobs:
 
   publish:
     runs-on: ubuntu-24.04
-    needs: [lint, unit, integration]
+    needs: [lint, unit, mima, integration]
     if: github.event_name != 'pull_request'
     steps:
       - name: Checkout current branch

build.sbt

@@ -77,6 +77,13 @@ addCommandAlias("itKyo", "integrationTestsKyo/test")
 
 addCommandAlias("exampleKyo", "examplesKyo/run")
 
+addCommandAlias(
+  "mima",
+  "all core/mimaReportBinaryIssues opentelemetry/mimaReportBinaryIssues compatCe/mimaReportBinaryIssues " +
+    "clientZio/mimaReportBinaryIssues clientCe/mimaReportBinaryIssues clientOx/mimaReportBinaryIssues " +
+    "clientPekko/mimaReportBinaryIssues clientKyo/mimaReportBinaryIssues"
+)
+
 addCommandAlias(
   "docAll",
   "all core/doc opentelemetry/doc compatCe/doc clientZio/doc clientCe/doc clientOx/doc clientPekko/doc clientKyo/doc"
@@ -96,6 +103,7 @@ lazy val root = project
 lazy val core = (projectMatrix in file("sage-core"))
   .settings(name := "sage-core")
   .settings(commonSettings)
+  .settings(mimaSettings)
   .settings(parallelUnitTests)
   .defaultAxes(VirtualAxis.jvm, VirtualAxis.scalaVersionAxis(scala3Version, scala3Version))
   .customRow(
@@ -109,6 +117,7 @@ lazy val opentelemetry = (projectMatrix in file("sage-opentelemetry"))
   .dependsOn(core)
   .settings(name := "sage-opentelemetry")
   .settings(commonSettings)
+  .settings(mimaSettings)
   .settings(parallelUnitTests)
   .settings(
     libraryDependencies ++= Seq(
@@ -130,6 +139,7 @@ lazy val compatCe = project
   .in(file("sage-compat-ce"))
   .settings(name := "sage-compat-ce")
   .settings(commonSettings)
+  .settings(mimaSettings)
   .settings(
     libraryDependencies ++= Seq(
       "org.typelevel" %% "cats-effect" % catsEffectVersion,
@@ -152,6 +162,7 @@ lazy val client = (projectMatrix in file("sage-client"))
   .enablePlugins(BuildInfoPlugin)
   .settings(name := "sage-client")
   .settings(commonSettings)
+  .settings(mimaSettings)
   .settings(parallelUnitTests)
   .settings(
     // compatLibrary emits an implicit Future anchor row; it's a compile-only baseline, never published
@@ -279,6 +290,14 @@ lazy val commonSettings = Def.settings(
   Test / fork                            := true
 )
 
+lazy val mimaSettings = Def.settings(
+  // the unpublished Future anchor row has no previous release to compare against
+  mimaPreviousArtifacts := {
+    if (moduleName.value.endsWith("-future")) Set.empty
+    else previousStableVersion.value.map(organization.value %% moduleName.value % _).toSet
+  }
+)
+
 // Only for container-free cells: integration suites each boot their own container, so running them in
 // parallel would multiply peak load and invite timing races
 lazy val parallelUnitTests = Def.settings(Test / testForkedParallel := true)

project/plugins.sbt

@@ -3,4 +3,5 @@ addSbtPlugin("com.eed3si9n"       % "sbt-projectmatrix" % "0.11.0")
 addSbtPlugin("com.eed3si9n"       % "sbt-buildinfo"     % "0.13.2")
 addSbtPlugin("org.scalameta"      % "sbt-scalafmt"      % "2.6.2")
 addSbtPlugin("com.github.sbt"     % "sbt-ci-release"    % "1.12.1")
+addSbtPlugin("com.typesafe"       % "sbt-mima-plugin"   % "1.2.1")
 addSbtPlugin("pl.project13.scala" % "sbt-jmh"           % "0.4.8")