fix case "skipped empty list and not null parameter"

GitOrigin-RevId: 42e81739dee2a0585c0b52825c7c4bfab3ef32e9

platform/object-serializer/src/CollectionBinding.kt

@@ -45,6 +45,11 @@ internal class CollectionBinding(type: ParameterizedType, context: BindingInitia
   private val collectionClass = ClassUtil.typeToClass(type)
 
   override fun deserialize(context: ReadContext): Collection<Any?> {
+    if (context.reader.type == IonType.INT) {
+      LOG.assertTrue(context.reader.intValue() == 0)
+      return emptyList()
+    }
+
     val result = createCollection()
     readInto(result, context)
     return result
@@ -53,6 +58,12 @@ internal class CollectionBinding(type: ParameterizedType, context: BindingInitia
   override fun serialize(obj: Any, context: WriteContext) {
     val writer = context.writer
     val collection = obj as Collection<*>
+    if (context.filter.skipEmptyCollection && collection.isEmpty()) {
+      // some value must be written otherwise on deserialize null will be used for constructor parameters (and it can be not expected)
+      writer.writeInt(0)
+      return
+    }
+
     writer.stepIn(IonType.LIST)
     collection.forEach(createItemConsumer(context))
     writer.stepOut()
@@ -64,6 +75,9 @@ internal class CollectionBinding(type: ParameterizedType, context: BindingInitia
       property.set(hostObject, null)
       return
     }
+    else if (type == IonType.INT /* empty collection if context.filter.skipEmptyCollection */) {
+      return
+    }
 
     @Suppress("UNCHECKED_CAST")
     var result = property.readUnsafe(hostObject) as MutableCollection<Any?>?
@@ -105,11 +119,27 @@ internal class CollectionBinding(type: ParameterizedType, context: BindingInitia
 internal class ArrayBinding(private val itemClass: Class<*>, context: BindingInitializationContext) : BaseCollectionBinding(itemClass, context) {
   override fun deserialize(context: ReadContext) = readArray(context)
 
+  override fun deserialize(hostObject: Any, property: MutableAccessor, context: ReadContext) {
+    val type = context.reader.type
+    if (type == IonType.NULL) {
+      property.set(hostObject, null)
+    }
+    else if (type != IonType.INT) {
+      property.set(hostObject, readArray(context))
+    }
+  }
+
   override fun serialize(obj: Any, context: WriteContext) {
+    val array = obj as Array<*>
     val writer = context.writer
+    if (context.filter.skipEmptyArray && array.isEmpty()) {
+      writer.writeInt(0)
+      return
+    }
+
     writer.stepIn(IonType.LIST)
     val consumer = createItemConsumer(context)
-    (obj as Array<*>).forEach { consumer.accept(it) }
+    array.forEach { consumer.accept(it) }
     writer.stepOut()
   }
 

platform/object-serializer/src/MapBinding.kt

@@ -14,8 +14,13 @@ internal class MapBinding(keyType: Type, valueType: Type, context: BindingInitia
   private val isKeyComparable = Comparable::class.java.isAssignableFrom(ClassUtil.typeToClass(keyType))
 
   override fun serialize(obj: Any, context: WriteContext) {
-    val writer = context.writer
     val map = obj as Map<*, *>
+    val writer = context.writer
+
+    if (context.filter.skipEmptyMap && map.isEmpty()) {
+      writer.writeInt(0)
+      return
+    }
 
     fun writeEntry(key: Any?, value: Any?) {
       if (key == null) {

platform/object-serializer/src/ObjectSerializer.kt

@@ -85,19 +85,29 @@ class ObjectSerializer {
 }
 
 interface SerializationFilter {
+  val skipEmptyCollection: Boolean
+    get() = false
+
+  val skipEmptyMap: Boolean
+    get() = false
+
+  val skipEmptyArray: Boolean
+    get() = false
+
   fun isSkipped(value: Any?): Boolean
 }
 
 object SkipNullAndEmptySerializationFilter : SerializationFilter {
-  override fun isSkipped(value: Any?): Boolean {
-    return when (value) {
-      null -> true
-      is Collection<*> -> value.isEmpty()
-      is Array<*> -> value.isEmpty()
-      is Map<*, *> -> value.isEmpty()
-      else -> false
-    }
-  }
+  override fun isSkipped(value: Any?) = value == null
+
+  override val skipEmptyCollection: Boolean
+    get() = true
+
+  override val skipEmptyMap: Boolean
+    get() = true
+
+  override val skipEmptyArray: Boolean
+    get() = true
 }
 
 class ObjectIdWriter {

platform/object-serializer/testSnapshots/several recursive reference.ion

@@ -2,6 +2,10 @@
   '@id':0,
   bean:{
     '@id':1,
-    bean:0
-  }
+    bean:0,
+    list:0,
+    children:0
+  },
+  list:0,
+  children:0
 }

platform/object-serializer/testSrc/NonDefaultConstructorTest.kt

@@ -19,13 +19,18 @@ class NonDefaultConstructorTest {
   @Rule
   val fsRule = InMemoryFsRule()
 
-  private fun test(bean: Any) = test(bean, testName, defaultTestWriteConfiguration)
+  private fun test(bean: Any, writeConfiguration: WriteConfiguration = defaultTestWriteConfiguration) = test(bean, testName, writeConfiguration)
 
   @Test
   fun `no default constructor`() {
     test(NoDefaultConstructorBean("foo", arrayListOf(42, 21)))
   }
 
+  @Test
+  fun `skipped empty list and not null parameter`() {
+    test(NoDefaultConstructorBean("foo", emptyList()), defaultTestWriteConfiguration.copy(filter = SkipNullAndEmptySerializationFilter))
+  }
+
   @Test
   fun `null string as arg`() {
     test(NullableArgBean("foo", null, ""))