Ktor 3.5.x auto-reload closes newly initialized Koin context

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Ktor 3.5.x auto-reload closes newly initialized Koin context

Describe the bug

koin-ktor appears to be incompatible with the create-then-swap auto-reload pattern introduced in Ktor v3.5.x via PR #5557. When the Ktor application is reloaded, the newly created Koin context is subsequently closed when the previous application is stopped.

To Reproduce

• Create a new project with ktor new and add the Koin plugin
• Set the Ktor version to 3.5.2 in settings.gradle.kts
• Set development: true in application.yaml
• Add the sample code below to Routing.kt
• Run ./gradlew run
• Make a code change (e.g. add a new line in Routing.kt)
• In a separate terminal, run ./gradlew build
• Access localhost:8080 to trigger the Ktor auto-reload

Snippet or Sample project to help reproduce

class Resource : AutoCloseable {
    init {
        println("INIT resource -> ${System.identityHashCode(this)}")
    }

    override fun close() {
        println("CLOSE resource -> ${System.identityHashCode(this)}")
    }
}

fun Application.configureRouting() {
    log.info("Init application ${System.identityHashCode(this)}")

    install(Koin) {
        slf4jLogger()

        val module = module {
            single { Resource() } onClose { it?.close() }
        }

        modules(module)
    }

    val resource = koin().get<Resource>()

    monitor.subscribe(ApplicationStopping) { appForEvent ->
        log.info(
            "Application stopping: " +
                "${System.identityHashCode(this)} -> " +
                "${System.identityHashCode(appForEvent)}"
        )
    }

    routing {
        get("/") {
            call.respondText("koin / ktor example")
        }
    }
}

Actual behavior

The logs below show that the newly created resource is closed after the auto-reload has completed:

2026-08-11 11:41:36.746 [main] INFO  Application - Init application 1130160902
2026-08-11 11:41:36.813 [main] INFO  [Koin] - Started 1 definitions in 1.728 ms
INIT resource -> 173440626
2026-08-11 11:41:36.831 [main] INFO  Application - Application started in 0.357 seconds.
2026-08-11 11:41:36.951 [main] INFO  Application - Responding at http://0.0.0.0:8080

2026-08-11 11:42:33.488 [eventLoopGroupProxy-3-1] INFO  Application - Changes in application detected.
2026-08-11 11:42:33.710 [eventLoopGroupProxy-3-1] INFO  Application - Init application 1065226841
2026-08-11 11:42:33.712 [eventLoopGroupProxy-3-1] INFO  [Koin] - Started 1 definitions in 0.054 ms
CLOSE resource -> 173440626
INIT resource -> 770784708
2026-08-11 11:42:33.714 [eventLoopGroupProxy-3-1] INFO  Application - Application auto-reloaded in 0.008 seconds.
2026-08-11 11:42:33.716 [eventLoopGroupProxy-3-1] INFO  Application - Application stopping: 1130160902 -> 1130160902
CLOSE resource -> 770784708
2026-08-11 11:42:33.716 [eventLoopGroupProxy-3-1] INFO  Application - Application stopping: 1065226841 -> 1130160902

In particular, the newly created application has identity 1065226841, while the ApplicationStopping event is for the previous application with identity 1130160902:

Application stopping: 1065226841 -> 1130160902

The Resource belonging to the newly created application (770784708) is then closed.

Expected behavior

The Koin context associated with the newly created application should remain active after auto-reload. Only the Koin context associated with the previous application should be closed.

The issue does not reproduce with Ktor 3.4.3. With the same sample application and koin-ktor:4.2.2, the previous resource is closed before the new application is initialized:

2026-08-11 11:36:06.464 [main] INFO  Application - Init application 1186657657
2026-08-11 11:36:06.590 [main] INFO  [Koin] - Started 1 definitions in 2.994 ms
INIT resource -> 271422148
2026-08-11 11:36:06.624 [main] INFO  Application - Application started in 0.703 seconds.
2026-08-11 11:36:06.855 [main] INFO  Application - Responding at http://0.0.0.0:8080

2026-08-11 11:36:34.309 [eventLoopGroupProxy-3-1] INFO  Application - Changes in application detected.
CLOSE resource -> 271422148
2026-08-11 11:36:34.512 [eventLoopGroupProxy-3-1] INFO  Application - Application stopping: 1186657657 -> 1186657657
2026-08-11 11:36:34.545 [eventLoopGroupProxy-3-1] INFO  Application - Init application 1370625743
2026-08-11 11:36:34.547 [eventLoopGroupProxy-3-1] INFO  [Koin] - Started 1 definitions in 0.115 ms
INIT resource -> 1534899786
2026-08-11 11:36:34.549 [eventLoopGroupProxy-3-1] INFO  Application - Application auto-reloaded in 0.016 seconds.

Versions

• koin-ktor: 4.2.2
• ktor: 3.5.2

The issue appears to be related to the Ktor 3.5.x auto-reload lifecycle change introduced by PR #5557.