Relocation breaks inner classes which contains '$' in name

[Him188]

The following Kotlin code is compiled with an inner class named $serializer by the Kotlin compiler.

package foo
@Serializable // This annotation instructs the compiler to generate an extra inner class named `$serializer`
enum class MyEnum {
    VALUE1
}

The qualified name of the inner class will be foo.MyEnum$$serializer.

If relocation is enabled, shadow runs RelocatorRemapper on the class. In org.objectweb.asm.commons.Remapper, it maps inner class names by substring-ing the name after the last $. So the resultant qualified name for the example will be foo.MyEnum$serializer (Note one $ is missing). This breaks Kotlin's class metadata and will cause AssertionError in runtime. See relevant issues like mamoe/mirai#2230.

---

Here's the org.objectweb.asm.commons.Remapper.mapInnerClassName for your reference.

  /**
   * Maps an inner class name to its new name. The default implementation of this method provides a
   * strategy that will work for inner classes produced by Java, but not necessarily other
   * languages. Subclasses can override.
   *
   * @param name the fully-qualified internal name of the inner class.
   * @param ownerName the internal name of the owner class of the inner class.
   * @param innerName the internal name of the inner class.
   * @return the new inner name of the inner class.
   */
  public String mapInnerClassName(
      final String name, final String ownerName, final String innerName) {
    final String remappedInnerName = this.mapType(name);
    if (remappedInnerName.contains("$")) {
      int index = remappedInnerName.lastIndexOf('$') + 1;
      while (index < remappedInnerName.length()
          && Character.isDigit(remappedInnerName.charAt(index))) {
        index++;
      }
      return remappedInnerName.substring(index);
    } else {
      return innerName;
    }
  }

Shadow Version

7.1.2

Gradle Version

7.3.0

Expected Behavior

Code runs successfully.

Actual Behavior

Gradle Build Script(s)

Content of Shadow JAR (jar tf <jar file> - post link to GIST if too long)