Add the ability to rename annotations added by the Scala compiler.

Author: shawjef3

gradle/dependencies.gradle

@@ -14,6 +14,8 @@ dependencies {
     implementation('org.vafer:jdependency:2.7.0') {
         exclude group: 'org.ow2.asm'
     }
+    // For Scala annotation remapping
+    implementation 'com.eed3si9n.jarjarabrams:jarjar-abrams-core_2.13:1.8.1'
 
     testImplementation('org.spockframework:spock-core:2.0-groovy-3.0') {
         exclude group: 'org.codehaus.groovy'

src/main/groovy/com/github/jengelman/gradle/plugins/shadow/impl/RelocatorRemapper.groovy

@@ -25,6 +25,9 @@ import com.github.jengelman.gradle.plugins.shadow.relocation.RelocatePathContext
 import com.github.jengelman.gradle.plugins.shadow.relocation.Relocator
 import com.github.jengelman.gradle.plugins.shadow.tasks.ShadowCopyAction.RelativeArchivePath
 import org.objectweb.asm.commons.Remapper
+import scala.Function1
+import scala.Option
+import scala.jdk.FunctionWrappers
 
 import java.util.regex.Matcher
 import java.util.regex.Pattern
@@ -40,10 +43,18 @@ class RelocatorRemapper extends Remapper {
 
     List<Relocator> relocators
     ShadowStats stats
+    Function1<String, Option<String>> scalaRenamer
 
     RelocatorRemapper(List<Relocator> relocators, ShadowStats stats) {
         this.relocators = relocators
         this.stats = stats
+        this.scalaRenamer =
+            new FunctionWrappers.FromJavaFunction(
+                (String string) -> {
+                    Optional<Relocator> maybe = relocators.stream().filter(x -> x.canRelocateClass(string)).findAny()
+                    Option.apply(maybe.map(it.relocateClass(new RelocateClassContext(string, stats))).orElse(null))
+                }
+            )
     }
 
     boolean hasRelocators() {

src/main/groovy/com/github/jengelman/gradle/plugins/shadow/tasks/ShadowCopyAction.groovy

@@ -1,5 +1,6 @@
 package com.github.jengelman.gradle.plugins.shadow.tasks
 
+import com.eed3si9n.jarjarabrams.scalasig.ScalaSigClassVisitor
 import com.github.jengelman.gradle.plugins.shadow.ShadowStats
 import com.github.jengelman.gradle.plugins.shadow.impl.RelocatorRemapper
 import com.github.jengelman.gradle.plugins.shadow.internal.GradleVersionUtil
@@ -348,7 +349,7 @@ class ShadowCopyAction implements CopyAction {
             // that use the constant pool to determine the dependencies of a class.
             ClassWriter cw = new ClassWriter(0)
 
-            ClassVisitor cv = new ClassRemapper(cw, remapper)
+            ClassVisitor cv = new ScalaSigClassVisitor(new ClassRemapper(cw, remapper), remapper.scalaRenamer)
 
             try {
                 cr.accept(cv, ClassReader.EXPAND_FRAMES)