Codable issues in multi-module transpiled app

[vdkdamian]

Are there known issues when using Codable in a multi-module app?

Encoding seems fine, but decoding seems to fail when the decodable model is defined in another module.

[marcprux]

Hmm … there shouldn't be any issues that I am aware of. We're definitely exercising both encoding and decoding Codable instances from other modules.

Can you post an error message? And ideally some or all of the Codable type?

[vdkdamian]

What does your Android/app/proguard-rules.pro file look like, compared to https://github.com/skiptools/skipapp-showcase/blob/main/Android/app/proguard-rules.pro?

-keeppackagenames **
-keep class skip.** { *; }
-keep class tools.skip.** { *; }
-keep class kotlin.jvm.functions.** {*;}
-keep class com.sun.jna.** { *; }
-dontwarn java.awt.**
-keep class * implements com.sun.jna.** { *; }
-keep class * implements skip.bridge.** { *; }
-keep class **._ModuleBundleAccessor_* { *; }
-keep class company.app.** { *; }
-dontwarn com.google.errorprone.annotations.CanIgnoreReturnValue
-dontwarn com.google.errorprone.annotations.Immutable

If you add the line -keep class prjcompany.** { *; } does it prevent the crash in release mode?

I'll test this out and come back to this. I'll try to do this tonight.

[vdkdamian]

Also, these are the structure of my module names:

PRJAPI
PRJData
PRJCompany

Main module:
CompanyApp

[vdkdamian]

I changed my proguard file to the following and now it's working fine.
Any ideas on why this is? Is something wrong with my project?

-keeppackagenames **
-keep class skip.** { *; }
-keep class tools.skip.** { *; }
-keep class kotlin.jvm.functions.** {*;}
-keep class com.sun.jna.** { *; }
-dontwarn java.awt.**
-keep class * implements com.sun.jna.** { *; }
-keep class * implements skip.bridge.** { *; }
-keep class **._ModuleBundleAccessor_* { *; }
-keep class company.app.** { *; }
-keep class prjapi.** { *; }
-keep class prjdata.** { *; }
-keep class prjcompany.** { *; }
-dontwarn com.google.errorprone.annotations.CanIgnoreReturnValue
-dontwarn com.google.errorprone.annotations.Immutable

[marcprux]

There's nothing wrong with the project. It looks like we need to improve the generation of @Keep annotations for Skip Codables.

Android's R8 (or Proguard) is a build step for optimizing and shrinking the Java bytecode for release builds. In some cases, this can cause issues when types need to be looked up by name (also known as "reflection"). Skip does need to sometimes do this for encoding/decoding as well as access to static members.

You can read all about customizing the R8/Proguard settings at https://developer.android.com/topic/performance/app-optimization/keep-rules-overview, but to make a long story short, you are probably safe with just sticking with the modifications you made to your app's configuration file. But do let us know if you run into any other crashes like this in the future.