Jackson, Kotlin and Proguard

Question

I'm facing an issue with Jackson and Kotlin Data classes when enabling Proguard. Jackson version: 2.9.1 Jackson Converter version: 2.3.0 Kotlin version: 1.2.51

Here's my proguard file:

-ignorewarnings

    # Jackson 2.x
-keepclassmembers class com.jgarin.remote.models.** {
  <init>(...);
  <fields>;
}
-keepclassmembers class * {
     @com.fasterxml.jackson.annotation.JsonCreator *;
     @com.fasterxml.jackson.annotation.JsonProperty *;
}

#Required for Kotlin!
-keep class kotlin.Metadata { *; }
-keep class kotlin.reflect.** { *; }
-keepclassmembers public class com.jgarin.** {
    public synthetic <methods>;
}

-keepattributes SourceFile,LineNumberTable,*Annotation*,EnclosingMethod,Signature,Exceptions,InnerClasses

Still, the app fails, throwing an exception:

E/RxCallAdapterWrapper: Retrofit exception occurred
    com.fasterxml.jackson.databind.exc.MismatchedInputException: Cannot construct instance of `com.jgarin.remote.models.responses.GetVerificationCodeResponse` (although at least one Creator exists): cannot deserialize from Object value (no delegate- or property-based Creator)

The rest of the stack trace is pretty much useless. I'm pretty sure I'm missing something obvious. Any help is appreciated. Thank you.

Are use using ObjectMapper#readValue? Take a look to this answer: https://stackoverflow.com/a/46571665/6421759 — Faustino Gagneten, Aug 21 '18 at 12:48
Yes, i do use ObjectMappers. And everything works fine until i turn on proguard. It seems to strip the apk of some important stuff that i cannot figure out how to keep. — Євген Гарастович, Aug 21 '18 at 13:18
Hmm.. Did you try the following proguard configuration? : https://stackoverflow.com/a/28022792/6421759 — Faustino Gagneten, Aug 21 '18 at 13:25
yes, i did. it didn't help, so i left only the lines that i know are useful. it feels like it has something to do with kotliin->java code generation. looks like some constructors are missing and that's what i have to figure out how to keep.do you have any ideas? — Євген Гарастович, Aug 21 '18 at 15:18
Let us [continue this discussion in chat](https://chat.stackoverflow.com/rooms/178463/discussion-between-faustino-gagneten-and--). — Faustino Gagneten, Aug 21 '18 at 15:19
Maybe this will help:https://stackoverflow.com/questions/27687128/how-to-setup-proguard-for-jackson-json-processor — pdem, Aug 27 '18 at 12:16
Maybe proguard is running before kotlin compilation. That could cause issues. — aglassman, Mar 29 '19 at 14:38

score -1 · Answer 1 · edited Dec 13 '19 at 00:46

-1

I think you need a no-args constructor in your classes to allow jackson to instanciate your class. Like this:

class AFHResponse(val MESSAGE: String, val CODE: String, val MIRRORS: Array<Mirror>) {
    private constructor() : this("", "", emptyArray())
}

Example from here

edited Dec 13 '19 at 00:46

Vaccano

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answered Dec 12 '19 at 19:59

binarynoise

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Thank you for the answer and welcome to Stack Overflow! Generally, Stack Overflow prefers answers that include the relevant data and code from links that are provided (in case the link goes offline in future years.) Consider adding the linked code as a sample in the answer and then referencing (via the link) where you got it from. – Vaccano Dec 13 '19 at 00:44

Jackson, Kotlin and Proguard

1 Answers1