[Kotlin] Get rid of Kotlin generated code of value checking

Look at the code below:

data class Account(val username: String, val password: String)

fun setAccount(account: Account) {
    print(account.username)
}

Check the code in Java format:

public static final class Account {
   @NotNull
   private final String username;
   @NotNull
   private final String password;

   @NotNull
   public final String getUsername() {
      return this.username;
   }

   @NotNull
   public final String getPassword() {
      return this.password;
   }

   public Account(@NotNull String username, @NotNull String password) {
      Intrinsics.checkParameterIsNotNull(username, "username");
      Intrinsics.checkParameterIsNotNull(password, "password");
      super();
      this.username = username;
      this.password = password;
   }

   @NotNull
   public final String component1() {
      return this.username;
   }

   @NotNull
   public final String component2() {
      return this.password;
   }

   @NotNull
   public final Account copy(@NotNull String username, @NotNull String password) {
      Intrinsics.checkParameterIsNotNull(username, "username");
      Intrinsics.checkParameterIsNotNull(password, "password");
      return new Account(username, password);
   }
   ....
}
public final void setAccount(@NotNull Account account) {
   Intrinsics.checkParameterIsNotNull(account, "account");
   String var2 = account.getUsername();
   boolean var3 = false;
   System.out.print(var2);
}

What’s the problem here ?

• Intrinsics.checkParameterIsNotNull() is generated
• The name of the argument are explored, “account”, “username” and “password”

Look at the obfuscated code:

public static final class C0374a {
    /* renamed from: a */
    public final String f8550a;
    /* renamed from: b */
    public final String f8551b;
    public C0374a(String str, String str2) {
        C3818i.m15316b(str, "username");
        C3818i.m15316b(str2, "password");
        this.f8550a = str;
        this.f8551b = str2;
    }
    /* renamed from: a */
    public final String mo12157a() {
        return this.f8550a;
    }
    
    ....
}
/* renamed from: a */
public final void mo12144a(C0374a aVar) {
    C3818i.m15316b(aVar, "account");
    System.out.print(aVar.mo12157a());
}

The Intrinsics.checkParameterIsNotNull() are still there.

Open mapping file in:

<project>\build\generated\outputs\mapping\<type>\mapping.txt

The classes in:

kotlin.jvm.internal.Intrinsics -> <your package>:
    boolean areEqual(java.lang.Object,java.lang.Object) -> a
    void checkExpressionValueIsNotNull(java.lang.Object,java.lang.String) -> a
    java.lang.Throwable sanitizeStackTrace(java.lang.Throwable) -> a
    java.lang.Throwable sanitizeStackTrace(java.lang.Throwable,java.lang.String) -> a
    void throwNpe() -> a
    void throwParameterIsNullException(java.lang.String) -> a
    void checkParameterIsNotNull(java.lang.Object,java.lang.String) -> b
    void throwUninitializedProperty(java.lang.String) -> b
    void throwUninitializedPropertyAccessException(java.lang.String) -> c
kotlin.jvm.internal.TypeIntrinsics -> <your package>:
    java.util.Map asMutableMap(java.lang.Object) -> a
    java.lang.Throwable sanitizeStackTrace(java.lang.Throwable) -> a
    java.lang.ClassCastException throwCce(java.lang.ClassCastException) -> a
    void throwCce(java.lang.Object,java.lang.String) -> a
    void throwCce(java.lang.String) -> a
    java.util.Map$Entry asMutableMapEntry(java.lang.Object) -> b
    java.util.Map castToMap(java.lang.Object) -> c
    java.util.Map$Entry castToMapEntry(java.lang.Object) -> d

How to get rid of them ?

Add the line below into proguard-rules.pro:

-assumenosideeffects class kotlin.jvm.internal.Intrinsics {
    public static void checkParameterIsNotNull(java.lang.Object, java.lang.String);
}

Summary:

• To follow the steps above to bypass the checking to increase the performance (must test the non-obfuscated version to ensure the app is working without the check)
• No non-onfuscated string are explored for hackers to save time to debug the app
• To decompile the app by yourself to see any method in Intrinsisc are used and add them into proguard-rules.pro !!

Used in:

Hong Alarm - Apps on Google Play