Hey guys, I have a simple data class for configura...

# spring

[André Martins]

Hey guys, I have a simple data class for configuration like the following

@Configuration
@ConfigurationProperties(prefix = "my-config")
data class MyConfig(
    var blacklist: List<BlackListEntry> = emptyList(),
)

data class BlackListEntry(
    val name: String,
    val values: List<String> = emptyList(),
)

And I'm using spring.config.import to import an additional application.yaml in my environment. The thing is I get java.lang.IllegalStateException: No setter found for property: blacklist
When I change the blacklist to be a MutableList it works, does spring first instantiate MyConfig for the base application.yaml and then try to call the setters with the additional imports? Shouldn't it merge the yamls first and only call the constructor once? Any ideias how can I keep the list as immutable?
Im using spring-boot 3.2 btw
Thanks in advance ✌️

[David Kubecka]

I'm using a similar pattern in my app. Only I'm using val everywhere. Did you try that?

[André Martins]

ya im using val but the thing is its a List instead of a MutableList

[David Kubecka]

I've found the exact same pattern, i.e. val list: List<...> = ... in my Spring app with imported config and it works for me. So perhaps the problem might be somewhere else?

[André Martins]

Ya but are u importing other application yaml/properties?

[André Martins]

using spring.config.import?

[David Kubecka]

Yes, I'm using spring.config.import

[David Kubecka]

Actually, I'm importing ALL app properties this way, i.e. no mixing.

[André Martins]

hmm

[André Martins]

can u share the example you have?

[André Martins]

might be some little detail

[David Kubecka]

Sorry, it's a private project 😞 But I see that you are actually using var: var blacklist =

[André Martins]

i will try to setup a minimal setup that reproduces my issue

[André Martins]

I believe the issue is with the "default"

[André Martins]

when i remove = emptyList() it works

[Pihentagy]

I think you can go with a val blacklist, but with a

mutableListOf()

default

[Jilles Soeters]

Why would you make configuration properties mutable? They should come from the config and mutating them sounds like asking for trouble

[Pihentagy]

True. But then why does it need setter?