InvalidMutabilityException when deserializing objects with UNKNOWN fields

[minaEweida]

This is happening when running for native when class is frozen, if you are deserializing a json that have UNKNOWN fields (which should be common in a non strict handling given that we might not want to deserialize some fields from a json response).

I see here which is added 6 days ago could be mutating the map in DescriptorSchemaCache.

val alternativeNamesMap = json.schemaCache.getOrPut(this, JsonAlternativeNamesKey, this::buildAlternativeNamesMap)

To Reproduce
If you run native for the test below it will fail with an InvalidMutabilityException.

class SerializerMutationTest {
    private val jsonNonStrict: Json by lazy {
        Json {
            isLenient = true
            ignoreUnknownKeys = true
            allowSpecialFloatingPointValues = true
            encodeDefaults = true
            useArrayPolymorphism = true
        }
    }

    @Test
    fun testDeserializeWithExtraFields() {
        freeze() // simulating a frozen environment
        val boxWithExtras = """
            {"width":25,"height":30,"color": "green"}
        """.trimIndent()
        val box = Box(25, 30)
        assertEquals(box, jsonNonStrict.decodeFromString(Box.serializer(), boxWithExtras))
    }
}

@Serializable
data class Box(
    val width: Int,
    val height: Int
)

Expected behavior
If I run this on 1.1.0 it passes. Is there a change that I missed in 1.2.1? Or is my configuration wrong?

Environment

• Library version: 1.2.1
• Kotlin platforms: Native

[Ribesg]

I have this issue too while upgrading a huge KMP project from even older versions of everything, I'll try version 1.1.0 for now, thanks for this report :)

Here is a stacktrace I just got, seems to be matching:

kotlin.native.concurrent.InvalidMutabilityException: mutation attempt of frozen kotlin.collections.HashMap@16e90e8
    at 0   Event                               0x000000010b5fb3ef kfun:kotlin.Throwable#<init>(kotlin.String?){} + 95 (/Users/teamcity1/teamcity_work/290aee0e088a1666/runtime/src/main/kotlin/kotlin/Throwable.kt:23:37)
    at 1   Event                               0x000000010b5f3b6d kfun:kotlin.Exception#<init>(kotlin.String?){} + 93 (/Users/teamcity1/teamcity_work/290aee0e088a1666/runtime/src/main/kotlin/kotlin/Exceptions.kt:23:44)
    at 2   Event                               0x000000010b5f3d4d kfun:kotlin.RuntimeException#<init>(kotlin.String?){} + 93 (/Users/teamcity1/teamcity_work/290aee0e088a1666/runtime/src/main/kotlin/kotlin/Exceptions.kt:34:44)
    at 3   Event                               0x000000010b62ccfd kfun:kotlin.native.concurrent.InvalidMutabilityException#<init>(kotlin.String){} + 93 (/Users/teamcity1/teamcity_work/290aee0e088a1666/runtime/src/main/kotlin/kotlin/native/concurrent/Freezing.kt:22:60)
    at 4   Event                               0x000000010b62e4ff ThrowInvalidMutabilityException + 431 (/Users/teamcity1/teamcity_work/290aee0e088a1666/runtime/src/main/kotlin/kotlin/native/concurrent/Internal.kt:93:11)
    at 5   Event                               0x000000010b79a260 MutationCheck + 128
    at 6   Event                               0x000000010b60ec92 kfun:kotlin.collections.HashMap.<set-length>#internal + 82 (/Users/teamcity1/teamcity_work/290aee0e088a1666/runtime/src/main/kotlin/kotlin/collections/HashMap.kt:16:17)
    at 7   Event                               0x000000010b613a91 kfun:kotlin.collections.HashMap#addKey(1:0){}kotlin.Int + 1233 (/Users/teamcity1/teamcity_work/290aee0e088a1666/runtime/src/main/kotlin/kotlin/collections/HashMap.kt:292:36)
    at 8   Event                               0x000000010b60fe85 kfun:kotlin.collections.HashMap#put(1:0;1:1){}1:1? + 357 (/Users/teamcity1/teamcity_work/290aee0e088a1666/runtime/src/main/kotlin/kotlin/collections/HashMap.kt:68:21)
    at 9   Event                               0x000000010b85acd3 kfun:kotlinx.serialization.json.internal.DescriptorSchemaCache#set(kotlinx.serialization.descriptors.SerialDescriptor;kotlinx.serialization.json.internal.DescriptorSchemaCache.Key<0:0>;0:0){0§<kotlin.Any>} + 771 (/opt/buildAgent/work/b2fef8360e1bcf3d/formats/json/commonMain/src/kotlinx/serialization/json/internal/SchemaCache.kt:23:58)
    at 10  Event                               0x000000010b85b080 kfun:kotlinx.serialization.json.internal.DescriptorSchemaCache#getOrPut(kotlinx.serialization.descriptors.SerialDescriptor;kotlinx.serialization.json.internal.DescriptorSchemaCache.Key<0:0>;kotlin.Function0<0:0>){0§<kotlin.Any>}0:0 + 576 (/opt/buildAgent/work/b2fef8360e1bcf3d/formats/json/commonMain/src/kotlinx/serialization/json/internal/SchemaCache.kt:29:9)
    at 11  Event                               0x000000010b854d88 kfun:kotlinx.serialization.json.internal#getJsonNameIndex__at__kotlinx.serialization.descriptors.SerialDescriptor(kotlinx.serialization.json.Json;kotlin.String){}kotlin.Int + 904 (/opt/buildAgent/work/b2fef8360e1bcf3d/formats/json/commonMain/src/kotlinx/serialization/json/internal/JsonNamesMap.kt:52:26)
    at 12  Event                               0x000000010b85db7e kfun:kotlinx.serialization.json.internal.StreamingJsonDecoder.decodeObjectIndex#internal + 734 (/opt/buildAgent/work/b2fef8360e1bcf3d/formats/json/commonMain/src/kotlinx/serialization/json/internal/StreamingJsonDecoder.kt:130:36)
    at 13  Event                               0x000000010b85cba6 kfun:kotlinx.serialization.json.internal.StreamingJsonDecoder#decodeElementIndex(kotlinx.serialization.descriptors.SerialDescriptor){}kotlin.Int + 502 (/opt/buildAgent/work/b2fef8360e1bcf3d/formats/json/commonMain/src/kotlinx/serialization/json/internal/StreamingJsonDecoder.kt:75:30)
    at 14  Event                               0x000000010bc557f0 kfun:com.mypackage.User.$serializer#deserialize(kotlinx.serialization.encoding.Decoder){}com.mypackage.User + 4000 (/somewhere/User.kt:1:1)
    at 15  Event                               0x000000010b858dde kfun:kotlinx.serialization.json.internal#decodeSerializableValuePolymorphic__at__kotlinx.serialization.json.JsonDecoder(kotlinx.serialization.DeserializationStrategy<0:0>){0§<kotlin.Any?>}0:0 + 2798 (/opt/buildAgent/work/b2fef8360e1bcf3d/formats/json/commonMain/src/kotlinx/serialization/json/internal/Polymorphic.kt:63:29)
    at 16  Event                               0x000000010b85be5a kfun:kotlinx.serialization.json.internal.StreamingJsonDecoder#decodeSerializableValue(kotlinx.serialization.DeserializationStrategy<0:0>){0§<kotlin.Any?>}0:0 + 202 (/opt/buildAgent/work/b2fef8360e1bcf3d/formats/json/commonMain/src/kotlinx/serialization/json/internal/StreamingJsonDecoder.kt:32:16)
    at 17  Event                               0x000000010b7f724d kfun:kotlinx.serialization.encoding.AbstractDecoder#decodeSerializableValue(kotlinx.serialization.DeserializationStrategy<0:0>;0:0?){0§<kotlin.Any?>}0:0 + 253 (/opt/buildAgent/work/b2fef8360e1bcf3d/core/commonMain/src/kotlinx/serialization/encoding/AbstractDecoder.kt:43:12)
    at 18  Event                               0x000000010b7f7c64 kfun:kotlinx.serialization.encoding.AbstractDecoder#decodeSerializableElement(kotlinx.serialization.descriptors.SerialDescriptor;kotlin.Int;kotlinx.serialization.DeserializationStrategy<0:0>;0:0?){0§<kotlin.Any?>}0:0 + 324 (/opt/buildAgent/work/b2fef8360e1bcf3d/core/commonMain/src/kotlinx/serialization/encoding/AbstractDecoder.kt:70:12)
    at 19  Event                               0x000000010b7f9b6f kfun:kotlinx.serialization.encoding.CompositeDecoder#decodeSerializableElement$default(kotlinx.serialization.descriptors.SerialDescriptor;kotlin.Int;kotlinx.serialization.DeserializationStrategy<0:0>;0:0?;kotlin.Int){0§<kotlin.Any?>}0:0 + 559 (/opt/buildAgent/work/b2fef8360e1bcf3d/core/commonMain/src/kotlinx/serialization/encoding/Decoding.kt:535:12)
    at 20  Event                               0x000000010b80217a kfun:kotlinx.serialization.internal.ListLikeSerializer#readElement(kotlinx.serialization.encoding.CompositeDecoder;kotlin.Int;1:2;kotlin.Boolean){} + 522 (/opt/buildAgent/work/b2fef8360e1bcf3d/core/commonMain/src/kotlinx/serialization/internal/CollectionSerializers.kt:80:39)
    at 21  Event                               0x000000010b80165d kfun:kotlinx.serialization.internal.AbstractCollectionSerializer#readElement$default(kotlinx.serialization.encoding.CompositeDecoder;kotlin.Int;1:2;kotlin.Boolean;kotlin.Int){} + 269 (/opt/buildAgent/work/b2fef8360e1bcf3d/core/commonMain/src/kotlinx/serialization/internal/CollectionSerializers.kt:51:24)
    at 22  Event                               0x000000010b8010be kfun:kotlinx.serialization.internal.AbstractCollectionSerializer#merge(kotlinx.serialization.encoding.Decoder;1:1?){}1:1 + 1518 (/opt/buildAgent/work/b2fef8360e1bcf3d/core/commonMain/src/kotlinx/serialization/internal/CollectionSerializers.kt:36:17)
    at 23  Event                               0x000000010b8012cc kfun:kotlinx.serialization.internal.AbstractCollectionSerializer#deserialize(kotlinx.serialization.encoding.Decoder){}1:1 + 204 (/opt/buildAgent/work/b2fef8360e1bcf3d/core/commonMain/src/kotlinx/serialization/internal/CollectionSerializers.kt:43:62)
    at 24  Event                               0x000000010b858dde kfun:kotlinx.serialization.json.internal#decodeSerializableValuePolymorphic__at__kotlinx.serialization.json.JsonDecoder(kotlinx.serialization.DeserializationStrategy<0:0>){0§<kotlin.Any?>}0:0 + 2798 (/opt/buildAgent/work/b2fef8360e1bcf3d/formats/json/commonMain/src/kotlinx/serialization/json/internal/Polymorphic.kt:63:29)
    at 25  Event                               0x000000010b85be5a kfun:kotlinx.serialization.json.internal.StreamingJsonDecoder#decodeSerializableValue(kotlinx.serialization.DeserializationStrategy<0:0>){0§<kotlin.Any?>}0:0 + 202 (/opt/buildAgent/work/b2fef8360e1bcf3d/formats/json/commonMain/src/kotlinx/serialization/json/internal/StreamingJsonDecoder.kt:32:16)
    at 26  Event                               0x000000010b838951 kfun:kotlinx.serialization.json.Json#decodeFromString(kotlinx.serialization.DeserializationStrategy<0:0>;kotlin.String){0§<kotlin.Any?>}0:0 + 753 (/opt/buildAgent/work/b2fef8360e1bcf3d/formats/json/commonMain/src/kotlinx/serialization/json/Json.kt:95:28)
    at 27  Event                               0x000000010bb83949 kfun:io.ktor.client.features.json.serializer.KotlinxSerializer#read(io.ktor.client.call.TypeInfo;io.ktor.utils.io.core.Input){}kotlin.Any + 1081 (/Users/administrator/Documents/agent/work/8d547b974a7be21f/ktor-client/ktor-client-features/ktor-client-json/ktor-client-serialization/common/src/io/ktor/client/features/json/serializer/KotlinxSerializer.kt:37:21)
    at 28  Event                               0x000000010bb80b95 kfun:io.ktor.client.features.json.JsonFeature.Feature.$install$lambda-1COROUTINE$1.invokeSuspend#internal + 2805 (/Users/administrator/Documents/agent/work/8d547b974a7be21f/ktor-client/ktor-client-features/ktor-client-json/common/src/io/ktor/client/features/json/JsonFeature.kt:161:53)
    at 29  Event                               0x000000010b61f180 kfun:kotlin.coroutines.native.internal.BaseContinuationImpl#resumeWith(kotlin.Result<kotlin.Any?>){} + 800 (/Users/teamcity1/teamcity_work/290aee0e088a1666/runtime/src/main/kotlin/kotlin/coroutines/ContinuationImpl.kt:30:39)

[sandwwraith]

Duplicate of #1450. You сan disable useAlternativeNames flag as a workaround