android - 使用 Proguard 混淆时 Gson EnumTypeAdapter 中的 AssertionError

Question

我的项目在序列化/反序列化期间在 Gson 中实现了一个 TypeAdapter，以保留对象的多态状态。无论如何，该项目在开发测试期间运行良好，但是当它使用 proguard 混淆 发布并经过测试时，它就崩溃了。

03-21 10:06:53.632: E/AndroidRuntime(12441): FATAL EXCEPTION: main
03-21 10:06:53.632: E/AndroidRuntime(12441): java.lang.AssertionError
03-21 10:06:53.632: E/AndroidRuntime(12441):    at com.google.gson.internal.bind.TypeAdapters$EnumTypeAdapter.<init>(SourceFile:724)
03-21 10:06:53.632: E/AndroidRuntime(12441):    at com.google.gson.internal.bind.TypeAdapters$26.create(SourceFile:753)
03-21 10:06:53.632: E/AndroidRuntime(12441):    at com.google.gson.Gson.getAdapter(SourceFile:353)
03-21 10:06:53.632: E/AndroidRuntime(12441):    at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$1.<init>(SourceFile:82)
03-21 10:06:53.632: E/AndroidRuntime(12441):    at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory.createBoundField(SourceFile:81)
03-21 10:06:53.632: E/AndroidRuntime(12441):    at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory.getBoundFields(SourceFile:118)
03-21 10:06:53.632: E/AndroidRuntime(12441):    at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory.create(SourceFile:72)
03-21 10:06:53.632: E/AndroidRuntime(12441):    at com.google.gson.Gson.getAdapter(SourceFile:353)
03-21 10:06:53.632: E/AndroidRuntime(12441):    at com.google.gson.Gson.toJson(SourceFile:578)
03-21 10:06:53.632: E/AndroidRuntime(12441):    at com.google.gson.Gson.toJsonTree(SourceFile:479)
03-21 10:06:53.632: E/AndroidRuntime(12441):    at com.google.gson.Gson.toJsonTree(SourceFile:458)
03-21 10:06:53.632: E/AndroidRuntime(12441):    at com.google.gson.Gson$3.serialize(SourceFile:137)

我的 Gson 特定的 proguard 配置是:

##---------------Begin: proguard configuration for Gson  ----------
# Gson uses generic type information stored in a class file when working with fields. Proguard
# removes such information by default, so configure it to keep all of it.
-keepattributes Signature

# For using GSON @Expose annotation
-keepattributes *Annotation*

# Gson specific classes
-keep class sun.misc.Unsafe { *; }
#-keep class com.google.gson.stream.** { *; }

# Application classes that will be serialized/deserialized over Gson
-keep class com.google.gson.examples.android.model.** { *; }

#This is extra - added by me to exclude gson obfuscation
-keep class com.google.gson.** { *; }

##---------------End: proguard configuration for Gson  ----------

我正在使用的 TypeAdapter 是:

public final class GsonWorkshiftAdapter implements JsonSerializer<IWorkshift>, JsonDeserializer<IWorkshift> {
    private static final String CLASSNAME = "CLASSNAME";
    private static final String INSTANCE  = "INSTANCE";

    @Override
    public JsonElement serialize(IWorkshift src, Type typeOfSrc, JsonSerializationContext context) {
        String className = src.getClass().getCanonicalName();
        JsonElement elem = context.serialize(src);

        JsonObject retValue = new JsonObject();
        retValue.addProperty(CLASSNAME, className);
        retValue.add(INSTANCE, elem);

        return retValue;
    }

    @Override
    public IWorkshift deserialize(JsonElement json, Type typeOfT, JsonDeserializationContext context) throws JsonParseException {
        JsonObject jsonObject =  json.getAsJsonObject();
        JsonPrimitive prim = (JsonPrimitive) jsonObject.get(CLASSNAME);
        String className = prim.getAsString();

        Class<?> klass = null;
        try { klass = Class.forName(className); }
        catch (ClassNotFoundException e) { throw new JsonParseException(e.getMessage()); }

        return context.deserialize(jsonObject.get(INSTANCE), klass);
    }
}

我针对 Gson 特有的这个错误进行了大量搜索，但找不到任何有用的答案。但是我发现 another question有类似的问题。

我们将不胜感激开发者社区的任何帮助。

Answer 1

似乎我们必须要求保留枚举的成员。将此添加到 proguard 配置文件中对我有用:

-keepclassmembers enum * { *; }

或者，如果你想更具体，

-keepclassmembers enum com.your.package.** { *; }