enable MiMa for Scala.js

Author: hamzaremmal

.github/workflows/stdlib.yaml

@@ -392,6 +392,24 @@ jobs:
       - name: Report MiMa issues in `tasty-core-bootstrapped`
         run: ./project/scripts/sbt tasty-core-bootstrapped-new/mimaReportBinaryIssues
 
+  mima-scala-library-sjs:
+    runs-on: ubuntu-latest
+    needs: scala-library-sjs
+    steps:
+      - name: Git Checkout
+        uses: actions/checkout@v5
+
+      - name: Set up JDK 17
+        uses: actions/setup-java@v5
+        with:
+          distribution: 'temurin'
+          java-version: 17
+          cache: 'sbt'
+
+      - uses: sbt/setup-sbt@v1
+      - name: Report MiMa issues in `scala-library-sjs`
+        run: ./project/scripts/sbt scala-library-sjs/mimaReportBinaryIssues
+
   #################################################################################################
   ########################################### TEST JOBS ###########################################
   #################################################################################################

project/Build.scala

@@ -1928,6 +1928,16 @@ object Build {
         }
       }).transform(node).head
       },
+      // Add configuration for MiMa
+      mimaCheckDirection := (compatMode match {
+        case CompatMode.BinaryCompatible          => "backward"
+        case CompatMode.SourceAndBinaryCompatible => "both"
+      }),
+      mimaExcludeAnnotations += "scala.annotation.experimental",
+      mimaPreviousArtifacts += ("org.scala-js" % "fat-stdlib_sjs1" % "3.7.3"),
+      mimaForwardIssueFilters := MiMaFilters.Scala3Library.ForwardsBreakingChanges,
+      mimaBackwardIssueFilters := MiMaFilters.Scala3Library.BackwardsBreakingChanges,
+      customMimaReportBinaryIssues("MiMaFilters.Scala3Library"),
       // Should we also patch .sjsir files
       keepSJSIR := true,
     )