为什么Proguard会删除方法的“桥”修饰符？

Question

我注意到Proguard删除了方法的桥修饰符，即使该类被排除在具有apply属性的混淆之外。我该如何避免这种行为？它打破了与第三方库的集成。 所以我有一个Scala函数对象，它有方法scala> classOf[TestFunction].getMethods.filter(m => m.getName == "apply" && !m.isBridge) res0: Array[java.lang.reflect.Method] = Array(public final double TestFunction.apply(java.lang.Object)) 。在混淆之前：

scala> classOf[TestFunction].getMethods.filter(m => m.getName == "apply" && !m.isBridge)
res0: Array[java.lang.reflect.Method] = Array(public final double TestFunction.apply(java.lang.Object), public final java.lang.Object TestFunction.apply(java.lang.Object))

混淆后：

-keepattributes Signature,*Annotation*
-keepattributes InnerClasses,EnclosingMethod
-keepattributes SourceFile,MethodParameters,Synthetic,Code,LineNumberTable

我需要这2个案例相似。

Proguard版本为5.3

UPD 我还保留以下属性：

    HttpBaseProtocolFilter filter = new HttpBaseProtocolFilter();
    filter.CacheControl.WriteBehavior = HttpCacheWriteBehavior.NoCache;
    filter.CacheControl.ReadBehavior = HttpCacheReadBehavior.MostRecent;

    filter.ServerCredential = new PasswordCredential(resourceUri.ToString(), username, password);

    HttpClient client = new HttpClient(filter);