ktor plugin ocassionally throws ScopeAlreadyCreatedException when trying to initialize RequestScope

[raphael-inglin-ergon]

Describe the bug Every few days we see exceptions in the logs of our productive system when trying to handling a request, resulting in the request failing.

First, koin fails to initialize the RequestScope:

org.koin.core.error.ScopeAlreadyCreatedException: Scope with id 'org.koin.ktor.plugin.RequestScope@1857368319' is already created
    at org.koin.core.registry.ScopeRegistry.createScope(ScopeRegistry.kt:64)
    at org.koin.core.Koin.createScope(Koin.kt:184)
    at org.koin.core.component.KoinScopeComponentKt.createScope(KoinScopeComponent.kt:45)
    at org.koin.core.component.KoinScopeComponentKt.createScope$default(KoinScopeComponent.kt:44)
    at org.koin.ktor.plugin.RequestScope.<init>(RequestScope.kt:29)
    at org.koin.ktor.plugin.KoinPluginKt$setupKoinScope$1.invokeSuspend(KoinPlugin.kt:69)
    at org.koin.ktor.plugin.KoinPluginKt$setupKoinScope$1.invoke(KoinPlugin.kt)
    at org.koin.ktor.plugin.KoinPluginKt$setupKoinScope$1.invoke(KoinPlugin.kt)
    at io.ktor.server.application.hooks.CallSetup$install$1.invokeSuspend(CommonHooks.kt:26)
        ...

Then when trying to finish the request, probably as a result of failing to create the scope initially:

java.lang.IllegalStateException: No instance for key AttributeKey: KOIN_SCOPE
    at io.ktor.util.Attributes$DefaultImpls.get(Attributes.kt:62)
    at io.ktor.util.AttributesJvmBase.get(AttributesJvm.kt:15)
    at org.koin.ktor.plugin.KoinPluginKt$setupKoinScope$2.invoke(KoinPlugin.kt:73)
    at org.koin.ktor.plugin.KoinPluginKt$setupKoinScope$2.invoke(KoinPlugin.kt:72)
    at io.ktor.server.application.hooks.ResponseSent$install$1.invokeSuspend(CommonHooks.kt:112)
        ...

It seems that there is a collision in the scopeId, that is automatically generated in KoinScopeComponent:

fun <T : Any> T.getScopeId() = this::class.getFullName() + "@" + this.hashCode()

To Reproduce We were unable to reproduce the issue. We see the same pattern occur every few days in the logs of our production system, randomly causing a request to fail.

Expected behavior

• RequestScope should always be initialized successfully, i.e. scopeIds automatically generated by koin should always be valid
  • Using uuids instead of hashCode() could be an option

Koin module and version:

• io.insert-koin:koin-core:3.5.6
• io.insert-koin:koin-ktor:3.5.6

Snippet or Sample project to help reproduce See above

[Gosunet]

Hello,

We have the same version of koin: 3.5.6, and we got the same random problem in production, which also caused some requests to fail.

[arnaudgiuliani]

getScopeId() is useful in android, but clashes here with Ktor. Can you ensure there is a clash with the scope id?

[raphael-inglin-ergon]

HI. As previously mentioned, we cannot reproduce the issue. However the stack trace does clearly indicate some kind of clash.

The exception is thrown in the createScopefunction of ScopeRegistry if there is already a Scope with this Id present. Since the RequestScope and its scopeId are automatically created by Koin when a request happens, this indicates that a new RequestScope just happens to have the same scopeId / hashCode as an already active Scope.

The scopeId is generated in KoinScopeComponent

It might also be that old Scopes are not removed correctly in some situations, increasing the likelihood of a collision but this is just speculation from my part.

Generally, hashCode() does not require two Objects to have different results, so it is plausible that collisions may occur.

[arnaudgiuliani]

would mean that hashcode is too close then? 🤔

[arnaudgiuliani]

I've added UUID scope id to allow wider generation. Should help 👍 See PR https://github.com/InsertKoinIO/koin/pull/1976