proguard Missing type parameter

Question

i try obfuscate my code of android app with ProGuard. But after this my app give exception at running:

11-15 01:46:26.818: W/System.err(21810): java.lang.RuntimeException: Missing type parameter.
11-15 01:46:26.828: W/System.err(21810):    at da.<init>(Unknown Source)
11-15 01:46:26.828: W/System.err(21810):    at gc.<init>(Unknown Source)
11-15 01:46:26.828: W/System.err(21810):    at fx.f(Unknown Source)
11-15 01:46:26.828: W/System.err(21810):    at com.yourshows.activity.UnwatchedActivity.onResume(Unknown Source)

I checked a mapping file and found this:

com.google.gson.reflect.TypeToken -> da:

I think it's lines in my app like:

        Type mapType = new TypeToken<Map<Integer, WatchedEpisodes>>(){}.getType(); // define generic type
        jsData = gson.fromJson(r, mapType);

I can not understand what conclusions should I do? Do not use variable name less then three characters or what?

UPD: answer

Answer 1

answer is: use this proguard.cfg

##---------------Begin: proguard configuration common for all Android apps ----------
-optimizationpasses 5
-dontusemixedcaseclassnames
-dontskipnonpubliclibraryclasses
-dontskipnonpubliclibraryclassmembers
-dontpreverify
-verbose
-dump class_files.txt 
-printseeds seeds.txt 
-printusage unused.txt 
-printmapping mapping.txt 
-optimizations !code/simplification/arithmetic,!field/*,!class/merging/*


-allowaccessmodification
-keepattributes *Annotation*
-renamesourcefileattribute SourceFile
-keepattributes SourceFile,LineNumberTable
-repackageclasses ''


-keep public class * extends android.app.Activity
-keep public class * extends android.app.Application
-keep public class * extends android.app.Service
-keep public class * extends android.content.BroadcastReceiver
-keep public class * extends android.content.ContentProvider
-keep public class * extends android.app.backup.BackupAgentHelper
-keep public class * extends android.preference.Preference
-keep public class com.android.vending.licensing.ILicensingService
-dontnote com.android.vending.licensing.ILicensingService


# Explicitly preserve all serialization members. The Serializable interface
# is only a marker interface, so it wouldn't save them.
-keepclassmembers class * implements java.io.Serializable {
    static final long serialVersionUID;
    private static final java.io.ObjectStreamField[] serialPersistentFields;
    private void writeObject(java.io.ObjectOutputStream);
    private void readObject(java.io.ObjectInputStream);
    java.lang.Object writeReplace();
    java.lang.Object readResolve();
}


# Preserve all native method names and the names of their classes.
-keepclasseswithmembernames class * {
    native <methods>;
}


-keepclasseswithmembernames class * {
    public <init>(android.content.Context, android.util.AttributeSet);
}


-keepclasseswithmembernames class * {
    public <init>(android.content.Context, android.util.AttributeSet, int);
}


# Preserve static fields of inner classes of R classes that might be accessed
# through introspection.
-keepclassmembers class **.R$* {
  public static <fields>;
}


# Preserve the special static methods that are required in all enumeration classes.
-keepclassmembers enum * {
    public static **[] values();
    public static ** valueOf(java.lang.String);
}


-keep public class * {
    public protected *;
}


-keep class * implements android.os.Parcelable {
  public static final android.os.Parcelable$Creator *;
}
##---------------End: proguard configuration common for all Android apps ----------


##---------------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


# 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.** { *; }


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

Big thanks to owner this project --> google-gson

---

UPD: google/gson has their example of proguard configuration for android applications.

see on github

They propose to use this template of configuration

##---------------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.** { *; }

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

Answer 2

Since I didn't notice the link in the question at first, here are the specific lines mentioned in the thread needed to get GSON to work with Proguard:

# 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

# 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.** { *; }

Answer 3

This issue can be solved by using a different way to create the TypeToken instance (for the parameterized type Map<Integer, WatchedEpisodes>):

Type collectionType = 
  TypeToken.get(
    $Gson$Types.newParameterizedTypeWithOwner(null,
      Map.class, Integer.class, WatchedEpisodes.class)).getType();

The next version of gson (I assume 2.8), will allow you to type this more easily:

Type collectionType =
  TypeToken.getParameterized(Map.class,
                             Integer.class,
                             WatchedEpisodes.class).getType();