Kodein + Ktor =冷冻kotlin.collections.HashMap的突变尝试--为什么？

Question

最近几天来，我一直在和这个例外作斗争。

我有一个具有以下依赖性的kotlin多平台项目：

• kotlin=1.5.10
• kodein=7.6.0
• ktor=1.6.0 (使用kotlin coroutines 1.5.0-本机-mt内部)

在尝试在本机中使用httpClient时，我一直被提到异常：

    at kotlin.Throwable#<init>(/Users/teamcity3/buildAgent/work/290aee0e088a1666/runtime/src/main/kotlin/kotlin/Throwable.kt:23)
    at kotlin.Exception#<init>(/Users/teamcity3/buildAgent/work/290aee0e088a1666/runtime/src/main/kotlin/kotlin/Exceptions.kt:23)
    at kotlin.RuntimeException#<init>(/Users/teamcity3/buildAgent/work/290aee0e088a1666/runtime/src/main/kotlin/kotlin/Exceptions.kt:34)
    at kotlin.native.concurrent.InvalidMutabilityException#<init>(/Users/teamcity3/buildAgent/work/290aee0e088a1666/runtime/src/main/kotlin/kotlin/native/concurrent/Freezing.kt:22)
    at <global>.ThrowInvalidMutabilityException(/Users/teamcity3/buildAgent/work/290aee0e088a1666/runtime/src/main/kotlin/kotlin/native/concurrent/Internal.kt:93)
    at <global>.MutationCheck(Unknown Source)
    at kotlin.collections.HashMap.<set-length>#internal(/Users/teamcity3/buildAgent/work/290aee0e088a1666/runtime/src/main/kotlin/kotlin/collections/HashMap.kt:16)
    at kotlin.collections.HashMap#addKey(/Users/teamcity3/buildAgent/work/290aee0e088a1666/runtime/src/main/kotlin/kotlin/collections/HashMap.kt:292)
    at kotlin.collections.HashMap#put(/Users/teamcity3/buildAgent/work/290aee0e088a1666/runtime/src/main/kotlin/kotlin/collections/HashMap.kt:68)
    at org.kodein.di.internal.DITreeImpl#find(/Users/runner/work/Kodein-DI/Kodein-DI/kodein-di/src/commonMain/kotlin/org/kodein/di/internal/DITreeImpl.kt:132)
    at org.kodein.di.DITree#find$default(/Users/runner/work/Kodein-DI/Kodein-DI/kodein-di/src/commonMain/kotlin/org/kodein/di/DITree.kt:36)
    at org.kodein.di.internal.DIContainerImpl#factory(/Users/runner/work/Kodein-DI/Kodein-DI/kodein-di/src/commonMain/kotlin/org/kodein/di/internal/DIContainerImpl.kt:158)
    at org.kodein.di.DIContainer#factory$default(/Users/runner/work/Kodein-DI/Kodein-DI/kodein-di/src/commonMain/kotlin/org/kodein/di/DIContainer.kt:32)
    at org.kodein.di.DIContainer#provider(/Users/runner/work/Kodein-DI/Kodein-DI/kodein-di/src/commonMain/kotlin/org/kodein/di/DIContainer.kt:76)
    at org.kodein.di.DIContainer#provider$default(/Users/runner/work/Kodein-DI/Kodein-DI/kodein-di/src/commonMain/kotlin/org/kodein/di/DIContainer.kt:75)
    at org.kodein.di.internal.DirectDIBaseImpl#Instance(/Users/runner/work/Kodein-DI/Kodein-DI/kodein-di/src/commonMain/kotlin/org/kodein/di/internal/DirectDIImpl.kt:30)
    at InvalidMutabilitySampleTest.<init>$lambda-6$lambda-5$lambda-4$lambda-3$lambda-2#internal(/Users/r.juszczyk/StudioProjects/lmhu-multiplatform-app/MultiplatformApp/src/iosTest/kotlin/InvalidMutabilitySampleTest.kt:26)
    at InvalidMutabilitySampleTest.$<init>$lambda-6$lambda-5$lambda-4$lambda-3$lambda-2$FUNCTION_REFERENCE$3.invoke#internal(/Users/r.juszczyk/StudioProjects/lmhu-multiplatform-app/MultiplatformApp/src/iosTest/kotlin/InvalidMutabilitySampleTest.kt:25)
    at InvalidMutabilitySampleTest.$<init>$lambda-6$lambda-5$lambda-4$lambda-3$lambda-2$FUNCTION_REFERENCE$3.$<bridge-UNNN>invoke(/Users/r.juszczyk/StudioProjects/lmhu-multiplatform-app/MultiplatformApp/src/iosTest/kotlin/InvalidMutabilitySampleTest.kt:25)
    at io.ktor.client.HttpClientConfig.install$<anonymous>_1#internal(/Users/administrator/Documents/agent/work/8d547b974a7be21f/ktor-client/ktor-client-core/common/src/io/ktor/client/HttpClientConfig.kt:69)
    at io.ktor.client.HttpClientConfig.$install$<anonymous>_1$FUNCTION_REFERENCE$17.invoke#internal(/Users/administrator/Documents/agent/work/8d547b974a7be21f/ktor-client/ktor-client-core/common/src/io/ktor/client/HttpClientConfig.kt:65)
    at io.ktor.client.HttpClientConfig.$install$<anonymous>_1$FUNCTION_REFERENCE$17.$<bridge-UNNN>invoke(/Users/administrator/Documents/agent/work/8d547b974a7be21f/ktor-client/ktor-client-core/common/src/io/ktor/client/HttpClientConfig.kt:65)
    at io.ktor.client.features.json.JsonFeature.Feature#prepare(/Users/administrator/Documents/agent/work/8d547b974a7be21f/ktor-client/ktor-client-features/ktor-client-json/common/src/io/ktor/client/features/json/JsonFeature.kt:129)
    at io.ktor.client.HttpClientConfig.install$<anonymous>_1-2#internal(/Users/administrator/Documents/agent/work/8d547b974a7be21f/ktor-client/ktor-client-core/common/src/io/ktor/client/HttpClientConfig.kt:77)
    at io.ktor.client.HttpClientConfig.$install$<anonymous>_1-2$FUNCTION_REFERENCE$18.invoke#internal(/Users/administrator/Documents/agent/work/8d547b974a7be21f/ktor-client/ktor-client-core/common/src/io/ktor/client/HttpClientConfig.kt:74)
    at io.ktor.client.HttpClientConfig.$install$<anonymous>_1-2$FUNCTION_REFERENCE$18.$<bridge-UNNN>invoke(/Users/administrator/Documents/agent/work/8d547b974a7be21f/ktor-client/ktor-client-core/common/src/io/ktor/client/HttpClientConfig.kt:74)
    at io.ktor.client.HttpClientConfig#install(/Users/administrator/Documents/agent/work/8d547b974a7be21f/ktor-client/ktor-client-core/common/src/io/ktor/client/HttpClientConfig.kt:97)
    at io.ktor.client.HttpClient#<init>(/Users/administrator/Documents/agent/work/8d547b974a7be21f/ktor-client/ktor-client-core/common/src/io/ktor/client/HttpClient.kt:172)
    at io.ktor.client.HttpClient#<init>(/Users/administrator/Documents/agent/work/8d547b974a7be21f/ktor-client/ktor-client-core/common/src/io/ktor/client/HttpClient.kt:81)
    at io.ktor.client#HttpClient(/Users/administrator/Documents/agent/work/8d547b974a7be21f/ktor-client/ktor-client-core/common/src/io/ktor/client/HttpClient.kt:43)

我在一次测试中成功地再现了那次坠机：

class InvalidMutabilitySampleTest {
    val di = DI {
        import(DI.Module("Some Module") {
            bind<Json>() with provider {
                Json {
                    prettyPrint = true
                    isLenient = true
                }
            }

            bind<HttpClient>() with provider {
                HttpClient{
                    install(JsonFeature) {
                        serializer = KotlinxSerializer(instance())
                    }
                }
            }
        })
    }

    val httpClient: HttpClient by di.instance()

    @Test
    fun invalidMutabilityTest() {
        println(httpClient)
    }

}

我还通过更改来修复它：

HttpClient{
   install(JsonFeature) {
      serializer = KotlinxSerializer(instance())
   }
}

至：

val json = instance<Json>()
HttpClient{
   install(JsonFeature) {
      serializer = KotlinxSerializer(json)
   }
}

然后我注意到HttpClient做了一件非常具体的事情--它将自己冻结在init块中。我成功地用以下示例代码再现了它：

class FrozenConstructor(val block: ()->Unit) {
    init {
        freeze()
    }
}

class InvalidMutabilitySampleTest2 {
    val di = DI {
        import(DI.Module("Some Module") {
            bind<String>() with provider {
                "lolo"
            }

            bind<FrozenConstructor>() with provider {
                FrozenConstructor{
                    instance<String>()
                }
            }
        })
    }

    val frozenConstructor: FrozenConstructor by di.instance()

    @Test
    fun invalidMutabilityTest() {
        println(frozenConstructor)
    }
}

所以我的理论是：

试图提供class

• FrozenConstructor的

1. kodein被创建并冻结了自己，它的成员引用kodein
2. kodein试图缓存提供的依赖，并尝试改变内部MutableMap，而内部MutableMap被冻结，一切都崩溃了

。

有人能确认这或多或少是正确的吗?如果不正确，可以纠正我吗？

另外，你们能提出最好的解决方法吗?还有其他等待解决的陷阱？

是科丁虫吗？

如果我使用的是with provider而不是with singleton，为什么kodein必须将一些东西存储在可变的地图中？

Answer 1

我想你已经猜到了。Ktor冻结了自己和它的所有配置，以确保它可以在Kotlin/原住民中的线程之间使用。Kodein假设您只会从一个线程中触摸到它，并且不安全。(无论这是一个限制、一个bug，还是一个设计缺陷，都可能有待解释。)

为了解决这些问题，您希望避免意外地捕获指向Kodein内部的this配置中的HttpClient引用。这样做的一个好方法是从HttpClient lambda之外的助手变量中获取DI中的实例，正如您已经发现的那样。

Answer 2

你是对的。FrozenConstructor冻结自己，因此它的block属性，作为一个lambda，冻结它的所有捕获，其中包括DI容器。

Kodein不支持冻结(因此也不支持原生多线程)。自从JB宣布要开发一个新的GC之后，这个决定已经决定不投资于使它与本地的多层兼容。