fix: Decoder does not represent the current node correctly (#617)

charleskorn · Nov 1, 2024 · dbb29e7 · dbb29e7
1 parent 0fa2c17
commit dbb29e7
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Showing 3 changed files with 67 additions and 4 deletions.
diff --git a/src/commonMain/kotlin/com/charleskorn/kaml/YamlListInput.kt b/src/commonMain/kotlin/com/charleskorn/kaml/YamlListInput.kt
@@ -18,6 +18,7 @@
 
 package com.charleskorn.kaml
 
+import kotlinx.serialization.DeserializationStrategy
 import kotlinx.serialization.ExperimentalSerializationApi
 import kotlinx.serialization.descriptors.SerialDescriptor
 import kotlinx.serialization.encoding.CompositeDecoder
@@ -65,6 +66,13 @@ internal class YamlListInput(val list: YamlList, yaml: Yaml, context: Serializer
     override fun decodeChar(): Char = currentElementDecoder.decodeChar()
     override fun decodeEnum(enumDescriptor: SerialDescriptor): Int = currentElementDecoder.decodeEnum(enumDescriptor)
 
+    override fun <T> decodeSerializableValue(deserializer: DeserializationStrategy<T>): T {
+        if (!haveStartedReadingElements) {
+            return super.decodeSerializableValue(deserializer)
+        }
+        return currentElementDecoder.decodeSerializableValue(deserializer)
+    }
+
     private val haveStartedReadingElements: Boolean
         get() = nextElementIndex > 0
 

diff --git a/src/commonMain/kotlin/com/charleskorn/kaml/YamlMapLikeInputBase.kt b/src/commonMain/kotlin/com/charleskorn/kaml/YamlMapLikeInputBase.kt
@@ -18,6 +18,7 @@
 
 package com.charleskorn.kaml
 
+import kotlinx.serialization.DeserializationStrategy
 import kotlinx.serialization.descriptors.SerialDescriptor
 import kotlinx.serialization.modules.SerializersModule
 
@@ -45,6 +46,15 @@ internal sealed class YamlMapLikeInputBase(map: YamlMap, yaml: Yaml, context: Se
     override fun decodeChar(): Char = fromCurrentValue { decodeChar() }
     override fun decodeEnum(enumDescriptor: SerialDescriptor): Int = fromCurrentValue { decodeEnum(enumDescriptor) }
 
+    override fun <T> decodeSerializableValue(deserializer: DeserializationStrategy<T>): T {
+        if (!haveStartedReadingEntries) {
+            return super.decodeSerializableValue(deserializer)
+        }
+        return fromCurrentValue {
+            decodeSerializableValue(deserializer)
+        }
+    }
+
     protected fun <T> fromCurrentValue(action: YamlInput.() -> T): T {
         try {
             return action(currentValueDecoder)

diff --git a/src/commonTest/kotlin/com/charleskorn/kaml/YamlReadingTest.kt b/src/commonTest/kotlin/com/charleskorn/kaml/YamlReadingTest.kt
@@ -2100,6 +2100,23 @@ class YamlReadingTest : FlatFunSpec({
                     result shouldBe ServerConfig(DatabaseListing(listOf(Database("A"), Database("B"))))
                 }
             }
+
+            context("decoding with a custom serializer for a non-root node") {
+                val theInput = """
+                    objectWithCustomSerializer:
+                        - cats
+                        - dogs
+                        - birds
+                """.trimIndent()
+
+                val result = Yaml.default.decodeFromString(ObjectContainingObjectWithCustomSerializer.serializer(), theInput)
+
+                test("decodes the Yaml as an ObjectContainingObjectWithCustomSerializer") {
+                    result shouldBe ObjectContainingObjectWithCustomSerializer(
+                        ObjectWithCustomSerializer("cats;dogs;birds"),
+                    )
+                }
+            }
         }
     }
 })
@@ -2204,10 +2221,7 @@ private object DecodingFromYamlNodeSerializer : KSerializer<DatabaseListing> {
     override fun deserialize(decoder: Decoder): DatabaseListing {
         check(decoder is YamlInput)
 
-        val currentMap = decoder.node.yamlMap.get<YamlMap>("databaseListing")
-        checkNotNull(currentMap)
-
-        val list = currentMap.entries.map { (_, value) ->
+        val list = decoder.node.yamlMap.entries.map { (_, value) ->
             decoder.yaml.decodeFromYamlNode(Database.serializer(), value)
         }
 
@@ -2216,3 +2230,34 @@ private object DecodingFromYamlNodeSerializer : KSerializer<DatabaseListing> {
 
     override fun serialize(encoder: Encoder, value: DatabaseListing) = throw UnsupportedOperationException()
 }
+
+@Serializable
+private data class ObjectContainingObjectWithCustomSerializer(
+    val objectWithCustomSerializer: ObjectWithCustomSerializer,
+)
+
+@Serializable(with = SerializerForObjectWithCustomSerializer::class)
+private data class ObjectWithCustomSerializer(
+    val combinedValues: String,
+)
+
+private object SerializerForObjectWithCustomSerializer : KSerializer<ObjectWithCustomSerializer> {
+    private const val ValuesSeparator = ";"
+
+    private val listSerializer = ListSerializer(String.serializer())
+    override val descriptor = listSerializer.descriptor
+
+    override fun serialize(encoder: Encoder, value: ObjectWithCustomSerializer) {
+        encoder.encodeSerializableValue(listSerializer, value.combinedValues.split(ValuesSeparator))
+    }
+
+    override fun deserialize(decoder: Decoder): ObjectWithCustomSerializer {
+        check(decoder is YamlInput)
+
+        // Intentionally parse the values from the current yaml node
+        val values = decoder.node.yamlList.items
+            .map { it.yamlScalar.content }
+
+        return ObjectWithCustomSerializer(values.joinToString(ValuesSeparator))
+    }
+}