Fix nullable QName parsing in a way that doesn't stop inline

structs from working. Do this by detecting the use of
nullableSerializable parsing (decodeNotNullMark). Otherwise there is
recursion.

Changelog.md

@@ -13,6 +13,8 @@ Fixes:
 - For attribute lists, make sure to collapse the whitespace.
 - When attributes have an `@XmlSerialName` annotation with a default namespace
   value, then this will result in a non-qualified attribute.
+- Fix nullable QName serialization (and probably other nullable inline-like)
+  serialization.
 
 # 0.86.1
 *(July 5, 2023)<br />*

core/src/commonMain/kotlin/nl/adaptivity/xmlutil/XmlReader.kt

@@ -1,7 +1,7 @@
 /*
- * Copyright (c) 2018.
+ * Copyright (c) 2023.
  *
- * This file is part of XmlUtil.
+ * This file is part of xmlutil.
  *
  * This file is licenced to you under the Apache License, Version 2.0 (the
  * "License"); you may not use this file except in compliance
@@ -67,15 +67,15 @@ public interface XmlReader : Closeable, Iterator<EventType> {
     public fun require(type: EventType, namespace: String?, name: String?) {
         when {
             eventType != type ->
-                throw XmlException("Type $eventType does not match expected type \"$type\"")
+                throw XmlException("Type $eventType does not match expected type \"$type\" ($locationInfo)")
 
             namespace != null &&
                     namespaceURI != namespace ->
-                throw XmlException("Namespace $namespaceURI does not match expected \"$namespace\"")
+                throw XmlException("Namespace $namespaceURI does not match expected \"$namespace\" ($locationInfo)")
 
             name != null &&
                     localName != name ->
-                throw XmlException("local name $localName does not match expected \"$name\"")
+                throw XmlException("local name $localName does not match expected \"$name\" ($locationInfo)")
         }
     }
 

serialization/src/commonMain/kotlin/nl/adaptivity/xmlutil/serialization/XMLDecoder.kt

@@ -1,7 +1,7 @@
 /*
- * Copyright (c) 2018.
+ * Copyright (c) 2023.
  *
- * This file is part of XmlUtil.
+ * This file is part of xmlutil.
  *
  * This file is licenced to you under the Apache License, Version 2.0 (the
  * "License"); you may not use this file except in compliance
@@ -300,6 +300,7 @@ internal open class XmlDecoderBase internal constructor(
         attrIndex: Int/* = -1*/,
         override val typeDiscriminatorName: QName?
     ) : XmlDecoder(xmlDescriptor, polyInfo, attrIndex) {
+        private var notNullChecked = false
 
         public var tagIdHolder: TagIdHolder? = null
 
@@ -317,6 +318,19 @@ internal open class XmlDecoderBase internal constructor(
             return value
         }
 
+        override fun decodeNotNullMark(): Boolean {
+            notNullChecked = true
+            return super.decodeNotNullMark()
+        }
+
+        override fun <T> decodeSerializableValue(deserializer: DeserializationStrategy<T>): T {
+            return when {
+                notNullChecked -> deserializer.deserialize(this)
+                else -> super.decodeSerializableValue(deserializer)
+            }
+            //return deserializer.deserialize(this) // Revert to default
+        }
+
         @ExperimentalSerializationApi
         override fun decodeInline(descriptor: SerialDescriptor): Decoder {
             tagIdHolder = object: TagIdHolder {
@@ -584,6 +598,8 @@ internal open class XmlDecoderBase internal constructor(
             if (((effectiveDeserializer as DeserializationStrategy<*>) == CompactFragmentSerializer) &&
                 (xmlDescriptor.getValueChild() == index)
             ) {
+                // handle missing compact fragments
+                if (nulledItemsIdx>=0) return (CompactFragment("") as T)
 //                input.require(EventType.START_ELEMENT, null)
                 return input.siblingsToFragment().let {
                     input.pushBackCurrent() // Make the closing tag again be the next read.

serialization/src/commonMain/kotlin/nl/adaptivity/xmlutil/serialization/XmlSerializationPolicy.kt

@@ -22,6 +22,7 @@ package nl.adaptivity.xmlutil.serialization
 import kotlinx.serialization.ExperimentalSerializationApi
 import kotlinx.serialization.KSerializer
 import kotlinx.serialization.SerializationException
+import kotlinx.serialization.builtins.nullable
 import kotlinx.serialization.descriptors.*
 import kotlinx.serialization.modules.SerializersModule
 import nl.adaptivity.xmlutil.*
@@ -601,7 +602,10 @@ private constructor(
     ): KSerializer<*>? =
         when (serializerParent.elementSerialDescriptor.serialName) {
             "javax.xml.namespace.QName?",
-            "javax.xml.namespace.QName" -> XmlQNameSerializer
+            "javax.xml.namespace.QName" -> when {
+                serializerParent.elementSerialDescriptor.isNullable -> XmlQNameSerializer.nullable
+                else -> XmlQNameSerializer
+            }
 
             else -> null
         }