@ConfigurationProperties annotated kotlin data classes containing properties with default value fail to initialize in 4.8.0

[bfg]

Expected Behavior

Assuming that you have configuration data class that is validated during initialization:

@ConfigurationProperties("app.controller")
data class ControllerCfg(
    val enabled: Boolean = true,
    @NotBlank val apiBase:String = "https://api.example.com/",
    @NotBlank val something: String = "some-value"
)

application configuration application.conf containing the following:

app {
  controller {
    enabled:    true
    #api-base:   "https://trololo.com/"
    something:  "trololo-something-value"
  }
}

This works perfectly fine on micronaut 4.7.6, but fails to initialize on 4.8.0 with:

Message: Validation failed for bean definition [com.github.bfg.mn48.ControllerCfg]
List of constraint violations:[
        com.github.bfg.mn48.ControllerCfg.apiBase - must not be blank
]
Path Taken:
new c.g.b.m.Controller(ControllerCfg cfg)
\---> new c.g.b.m.Controller([ControllerCfg cfg])
      \---> new @i.m.c.a.ConfigurationProperties("app.controller") c.g.b.m.ControllerCfg(boolean enabled, [String apiBase], String something)

It's obvious that apiBase property default value is not applied if it's absent in the config file. I really like and prefer 4.7.x behaviour in this context because some configuration constructs can be only easily specified in the code and have to be rarely changed in the actual config.

Actual Behaviour

Exception is being thrown

Steps To Reproduce

Reproducer: https://github.com/bfg/mn-48-kotlin-data-class-defvalue

Environment Information

• OSX 15.2
• JDK 21

Example Application

https://github.com/bfg/mn-48-kotlin-data-class-defvalue

Version

4.8.0