Fix missing nullable constructor parameters deserialization

pom.xml

@@ -8,7 +8,7 @@
     <parent>
         <groupId>com.fasterxml.jackson</groupId>
         <artifactId>jackson-base</artifactId>
-        <version>2.13.0-rc2-SNAPSHOT</version>
+        <version>2.13.0-SNAPSHOT</version>
     </parent>
     <groupId>com.fasterxml.jackson.module</groupId>
     <artifactId>jackson-module-kotlin</artifactId>

release-notes/CREDITS-2.x

@@ -32,6 +32,10 @@ wrongwrong (k163377@github)
 * Contributed #438: Fixed mapping failure when `private` `companion object` is named
   (2.13)
 
+Dmitri Domanine (novtor@github)
+* Contributed fix for #490: Missing value of type JsonNode? is deserialized as NullNode instead of null
+  (2.13)
+
 Marshall Pierce (marshallpierce@github)
 * #474: Reported disrespect for @JsonProperty on parent class
   (2.12.NEXT)

src/main/kotlin/com/fasterxml/jackson/module/kotlin/KotlinValueInstantiator.kt

@@ -101,8 +101,13 @@ internal class KotlinValueInstantiator(
                 }
                 tempParamVal
             } else {
-                // trying to get suitable "missing" value provided by deserializer
-                jsonProp.valueDeserializer?.getNullValue(ctxt)
+                if(paramDef.type.isMarkedNullable) {
+                    // do not try to create any object if it is nullable and the value is missing
+                    null
+                } else {
+                    // to get suitable "missing" value provided by deserializer
+                    jsonProp.valueDeserializer?.getAbsentValue(ctxt)
+                }
             }
 
             if (paramVal == null && ((nullToEmptyCollection && jsonProp.type.isCollectionLikeType) || (nullToEmptyMap && jsonProp.type.isMapLikeType))) {

src/test/kotlin/com/fasterxml/jackson/module/kotlin/test/github/Github490.kt

@@ -0,0 +1,81 @@
+package com.fasterxml.jackson.module.kotlin.test.github
+
+import com.fasterxml.jackson.databind.JsonNode
+import com.fasterxml.jackson.databind.node.NullNode
+import com.fasterxml.jackson.module.kotlin.jacksonObjectMapper
+import com.fasterxml.jackson.module.kotlin.readValue
+import org.hamcrest.CoreMatchers
+import org.hamcrest.MatcherAssert.assertThat
+import org.junit.Test
+
+class TestGithub490 {
+    val mapper = jacksonObjectMapper()
+    val value: DataClassWithAllNullableParams = mapper.readValue(
+        "{" +
+                "\"jsonNodeValueWithNullAsDefaultProvidedNull\":null, " +
+                "\"jsonNodeValueProvidedNull\":null}"
+    )
+
+    @Test
+    fun testKotlinDeserialization_intValue() {
+        assertThat(
+            "Nullable missing Int value should be deserialized as null",
+            value.intValue,
+            CoreMatchers.nullValue()
+        )
+    }
+
+    @Test
+    fun testKotlinDeserialization_stringValue() {
+        assertThat(
+            "Nullable missing String value should be deserialized as null",
+            value.stringValue,
+            CoreMatchers.nullValue()
+        )
+    }
+
+    @Test
+    fun testKotlinDeserialization_jsonNodeValue() {
+        assertThat(
+            "Nullable missing JsonNode value should be deserialized as null and not as NullNode",
+            value.jsonNodeValue,
+            CoreMatchers.nullValue()
+        )
+    }
+
+    @Test
+    fun testKotlinDeserialization_jsonNodeValueProvidedNull() {
+        assertThat(
+            "Nullable JsonNode value provided as null should be deserialized as NullNode",
+            value.jsonNodeValueProvidedNull,
+            CoreMatchers.equalTo(NullNode.instance)
+        )
+    }
+
+    @Test
+    fun testKotlinDeserialization_jsonNodeValueWithNullAsDefault() {
+        assertThat(
+            "Nullable by default missing JsonNode value should be deserialized as null and not as NullNode",
+            value.jsonNodeValueWithNullAsDefault,
+            CoreMatchers.nullValue()
+        )
+    }
+
+    @Test
+    fun testKotlinDeserialization_jsonNodeValueWithNullAsDefaultProvidedNull() {
+        assertThat(
+            "Nullable by default JsonNode with provided null value in payload should be deserialized as NullNode",
+            value.jsonNodeValueWithNullAsDefaultProvidedNull,
+            CoreMatchers.equalTo(NullNode.instance)
+        )
+    }
+}
+
+data class DataClassWithAllNullableParams(
+    val intValue: Int?,
+    val stringValue: String?,
+    val jsonNodeValue: JsonNode?,
+    val jsonNodeValueProvidedNull: JsonNode?,
+    val jsonNodeValueWithNullAsDefault: JsonNode? = null,
+    val jsonNodeValueWithNullAsDefaultProvidedNull: JsonNode? = null
+)