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

Question

最近几天我一直在与这个异常作斗争。

我有一个包含这些依赖项的 kotlin 多平台项目:

• kotlin=1.5.10
• kodein=7.6.0
• ktor=1.6.0(内部使用 kotlin 协程 1.5.0-native-mt)

我在尝试在 native 中使用 httpClient 时遇到了异常:

    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)

我设法在测试中重现了该崩溃:

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)
    }

}

我还设法通过更改来修复它:

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

到:

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——它在 init block 中卡住了自己。我设法用这个示例代码重现了它:

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)
    }
}

所以我的理论如下:

1. kodein 尝试提供 FrozenConstructor 类
2. FrozenConstructor 被创建并卡住自己，它的成员引用了kodein
3. kodein 尝试缓存提供的依赖项并尝试改变内部的 MutableMap，它被卡住并且一切都崩溃了

有人可以确认这或多或少是正确的，如果不是，请纠正我？

你们还能建议最好的处理方法，以及其他等待在那里的陷阱吗？

这是一个kodein错误吗？

如果我使用的是 with provider 而不是 with singleton，为什么 kodein 必须将某些内容存储在可变映射中？

Answer 1

我想你已经很清楚了。 Ktor 卡住自身及其所有配置，以确保它可以在 Kotlin/Native 中跨线程使用。 Kodein 假设您只会从一个线程中触摸它，并且卡住是不安全的。 (无论这是限制、错误还是设计缺陷都可能需要解释。)

要解决这些问题，您需要避免在 HttpClient 配置中意外捕获引用 Kodein 内部的 this 引用。如您所见，一个好方法是在 HttpClient lambda 之外的辅助变量中从 DI 中获取实例。