Importing another configuration file in Ktor 0.9.3 throws exception

Question

In a Ktor 0.9.3 application, I want to have different .conf files for different environments, where I extend one main .conf file. However, I am getting the following exception:

Exception in thread "main" com.typesafe.config.ConfigException$NotResolved: called valueType() on value with unresolved substitutions, need to Config#resolve() first, see API docs
    at com.typesafe.config.impl.ConfigDelayedMerge.valueType(ConfigDelayedMerge.java:46)
    at com.typesafe.config.impl.SimpleConfig.hasPath(SimpleConfig.java:96)
    at io.ktor.config.HoconApplicationConfigKt.tryGetString(HoconApplicationConfig.kt:33)
    at io.ktor.server.engine.CommandLineKt$commandLineEnvironment$environment$1.invoke(CommandLine.kt:64)
    at io.ktor.server.engine.CommandLineKt$commandLineEnvironment$environment$1.invoke(CommandLine.kt)
    at io.ktor.server.engine.ApplicationEngineEnvironmentBuilder.build(ApplicationEngineEnvironment.kt:55)
    at io.ktor.server.engine.ApplicationEngineEnvironmentKt.applicationEngineEnvironment(ApplicationEngineEnvironment.kt:38)
    at io.ktor.server.engine.CommandLineKt.commandLineEnvironment(CommandLine.kt:50)
    at io.ktor.server.netty.DevelopmentEngine.main(DevelopmentEngine.kt:13)
    at ApplicationKt.main(application.kt:24)

This is my application.conf file:

ktor {
    deployment {
        port = 8080
        port = ${?PORT}
        watch = [ website ]
    }
    application {
        modules = [ ApplicationKt.module ]
    }
}

ui {
  hotreload {
    enabled = false
    path-prefix = "http://localhost:3000"
  }
}

And the one extending it that I want to use:

include "application.conf"

ui.hotreload.enabled = true

Any ideas what is going wrong and how to fix it?

Answer 1

According to the issue I opened on Ktor's GitHub page, this is a known bug for which a PR fixing it has been merged already, so it should be fixed in the next release. As a matter of fact, it works as intended in version 0.9.4-alpha-2