GSON ignoring kotlin data class null-safety and default value

[Mopriestt]

This results in Gson creating data objects with possible null values for non-null variables in the following cases:
Any variable that is marked as non-null in the data class but is missing in the JSON
Any variable that is an Enum type and the value passed from the server doesn’t have a matching Enum value on the client

[lyubomyr-shaydariv]

Duplicate of #1148, #1444 and #1550 .

[paulschuetz]

this issue is so crucial in my opinion... Is there an update?

[aljidy]

Is this not intentional behaviour? See this:

https://stackoverflow.com/a/45793703

Edit: Found the issue. GSON uses the magic sun.misc.Unsafe class which has an allocateInstance method which is obviously considered very unsafe because what it does is skip initialization (constructors/field initializers and the like) and security checks. So there is your answer why a Kotlin non-nullable field can be null. Offending code is in com/google/gson/internal/ConstructorConstructor.java:223

Some interesting details about the Unsafe class: http://mishadoff.com/blog/java-magic-part-4-sun-dot-misc-dot-unsafe/

[sparklexin]

You can use https://github.com/square/moshi, if null-safety check failed, it will throw an exception.

If you want kotlin data class null-safety and default value using moshi, you can reference https://github.com/sparklexin/moshi-kotlin-nullsafe