"Unexpected JSON token at offset" error when deserializing Map<Boolean, Boolean>

[arkivanov]

Describe the bug

Serializing and deserializing Map<Boolean, Boolean> with Json throws kotlinx.serialization.json.internal.JsonDecodingException.

kotlinx.serialization.json.internal.JsonDecodingException: Unexpected JSON token at offset 15: Expected valid boolean literal prefix, but had 'false' at path: $.map
JSON input: {"map":{"false":true,"true":false}}
	at kotlinx.serialization.json.internal.JsonExceptionsKt.JsonDecodingException(JsonExceptions.kt:24)
	at kotlinx.serialization.json.internal.JsonExceptionsKt.JsonDecodingException(JsonExceptions.kt:32)
	at kotlinx.serialization.json.internal.AbstractJsonLexer.fail(AbstractJsonLexer.kt:598)
	at kotlinx.serialization.json.internal.AbstractJsonLexer.fail$default(AbstractJsonLexer.kt:596)
	at kotlinx.serialization.json.internal.AbstractJsonLexer.consumeBoolean(AbstractJsonLexer.kt:735)
	at kotlinx.serialization.json.internal.AbstractJsonLexer.consumeBoolean(AbstractJsonLexer.kt:694)
	at kotlinx.serialization.json.internal.StreamingJsonDecoder.decodeBoolean(StreamingJsonDecoder.kt:280)
	at kotlinx.serialization.internal.BooleanSerializer.deserialize(Primitives.kt:104)
	at kotlinx.serialization.internal.BooleanSerializer.deserialize(Primitives.kt:100)
	at kotlinx.serialization.json.internal.StreamingJsonDecoder.decodeSerializableValue(StreamingJsonDecoder.kt:70)
	at kotlinx.serialization.encoding.AbstractDecoder.decodeSerializableValue(AbstractDecoder.kt:43)
	at kotlinx.serialization.encoding.AbstractDecoder.decodeSerializableElement(AbstractDecoder.kt:70)
	at kotlinx.serialization.json.internal.StreamingJsonDecoder.decodeSerializableElement(StreamingJsonDecoder.kt:165)
	at kotlinx.serialization.encoding.CompositeDecoder$DefaultImpls.decodeSerializableElement$default(Decoding.kt:533)
	at kotlinx.serialization.internal.MapLikeSerializer.readElement(CollectionSerializers.kt:100)
	at kotlinx.serialization.internal.MapLikeSerializer.readElement(CollectionSerializers.kt:84)
	at kotlinx.serialization.internal.AbstractCollectionSerializer.readElement$default(CollectionSerializers.kt:51)
	at kotlinx.serialization.internal.AbstractCollectionSerializer.merge(CollectionSerializers.kt:36)
	at kotlinx.serialization.internal.AbstractCollectionSerializer.deserialize(CollectionSerializers.kt:43)
	at kotlinx.serialization.json.internal.StreamingJsonDecoder.decodeSerializableValue(StreamingJsonDecoder.kt:70)
	at kotlinx.serialization.encoding.AbstractDecoder.decodeSerializableValue(AbstractDecoder.kt:43)
	at kotlinx.serialization.encoding.AbstractDecoder.decodeSerializableElement(AbstractDecoder.kt:70)
	at kotlinx.serialization.json.internal.StreamingJsonDecoder.decodeSerializableElement(StreamingJsonDecoder.kt:165)
	at com.arkivanov.essenty.statekeeper.CodingTest$Data$$serializer.deserialize(CodingTest.kt:27)
	at com.arkivanov.essenty.statekeeper.CodingTest$Data$$serializer.deserialize(CodingTest.kt:27)
	at kotlinx.serialization.json.internal.StreamingJsonDecoder.decodeSerializableValue(StreamingJsonDecoder.kt:70)
	at kotlinx.serialization.json.Json.decodeFromString(Json.kt:107)
	at com.arkivanov.essenty.statekeeper.CodingTest.foo(CodingTest.kt:22)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77)
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.base/java.lang.reflect.Method.invoke(Method.java:568)
	at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:59)
	at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
	at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:56)
	at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
	at org.junit.runners.ParentRunner$3.evaluate(ParentRunner.java:306)
	at org.junit.runners.BlockJUnit4ClassRunner$1.evaluate(BlockJUnit4ClassRunner.java:100)
	at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:366)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:103)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:63)
	at org.junit.runners.ParentRunner$4.run(ParentRunner.java:331)
	at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:79)
	at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:329)
	at org.junit.runners.ParentRunner.access$100(ParentRunner.java:66)
	at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:293)
	at org.junit.runners.ParentRunner$3.evaluate(ParentRunner.java:306)
	at org.junit.runners.ParentRunner.run(ParentRunner.java:413)
	at org.gradle.api.internal.tasks.testing.junit.JUnitTestClassExecutor.runTestClass(JUnitTestClassExecutor.java:108)
	at org.gradle.api.internal.tasks.testing.junit.JUnitTestClassExecutor.execute(JUnitTestClassExecutor.java:58)
	at org.gradle.api.internal.tasks.testing.junit.JUnitTestClassExecutor.execute(JUnitTestClassExecutor.java:40)
	at org.gradle.api.internal.tasks.testing.junit.AbstractJUnitTestClassProcessor.processTestClass(AbstractJUnitTestClassProcessor.java:60)
	at org.gradle.api.internal.tasks.testing.SuiteTestClassProcessor.processTestClass(SuiteTestClassProcessor.java:52)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77)
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.base/java.lang.reflect.Method.invoke(Method.java:568)
	at org.gradle.internal.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:36)
	at org.gradle.internal.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:24)
	at org.gradle.internal.dispatch.ContextClassLoaderDispatch.dispatch(ContextClassLoaderDispatch.java:33)
	at org.gradle.internal.dispatch.ProxyDispatchAdapter$DispatchingInvocationHandler.invoke(ProxyDispatchAdapter.java:94)
	at jdk.proxy1/jdk.proxy1.$Proxy2.processTestClass(Unknown Source)
	at org.gradle.api.internal.tasks.testing.worker.TestWorker$2.run(TestWorker.java:176)
	at org.gradle.api.internal.tasks.testing.worker.TestWorker.executeAndMaintainThreadName(TestWorker.java:129)
	at org.gradle.api.internal.tasks.testing.worker.TestWorker.execute(TestWorker.java:100)
	at org.gradle.api.internal.tasks.testing.worker.TestWorker.execute(TestWorker.java:60)
	at org.gradle.process.internal.worker.child.ActionExecutionWorker.execute(ActionExecutionWorker.java:56)
	at org.gradle.process.internal.worker.child.SystemApplicationClassLoaderWorker.call(SystemApplicationClassLoaderWorker.java:113)
	at org.gradle.process.internal.worker.child.SystemApplicationClassLoaderWorker.call(SystemApplicationClassLoaderWorker.java:65)
	at worker.org.gradle.process.internal.worker.GradleWorkerMain.run(GradleWorkerMain.java:69)
	at worker.org.gradle.process.internal.worker.GradleWorkerMain.main(GradleWorkerMain.java:74)

To Reproduce

 @Test
    fun foo() {
        val data = Data(map = mapOf(false to true, true to false))

        val newData = Json.decodeFromString(Data.serializer(), Json.encodeToString(Data.serializer(), data))

        assertEquals(data, newData)
    }

    @Serializable
    data class Data(
        val map: Map<Boolean, Boolean>,
    )

Expected behavior

The test passes.

Environment

• Kotlin version: 1.9.0
• Library version: 1.6.0
• Kotlin platforms: JVM, iOS
• Gradle version: 8.0.2
• IDE version: IntelliJ IDEA 2023.2

[sandwwraith]

This is another issue of unstrict Json type mapping: json keys are always quoted, but Map<Boolean, Boolean> serializer assumes that keys should be unquoted because they're booleans, not strings.

However, given that we allow this quote-unquote relaxation for Map<Int, ...>, we should allow similar for booleans too.

[arkivanov]

Thanks for fixing the issue! Are there any expectations for releasing the fix?

[sandwwraith]

It will be in 1.6.1, which should come out in a month or two.