handle null pointer issue

Author: PJ Fanning

src/main/scala/com/fasterxml/jackson/module/scala/introspect/ScalaAnnotationIntrospectorModule.scala

@@ -123,22 +123,26 @@ object ScalaAnnotationIntrospector extends NopAnnotationIntrospector with ValueI
 
   class ScalaValueInstantiator(delegate: StdValueInstantiator, config: DeserializationConfig, descriptor: BeanDescriptor) extends StdValueInstantiator(delegate) {
 
-    private val overriddenConstructorArguments = {
+    private val overriddenConstructorArguments: Array[SettableBeanProperty] = {
       val args = delegate.getFromObjectArguments(config)
-
-      args.map {
-        case creator: CreatorProperty =>
-          // Locate the constructor param that matches it
-          descriptor.properties.find(_.param.exists(_.index == creator.getCreatorIndex)) match {
-            case Some(PropertyDescriptor(name, Some(ConstructorParameter(_, _, Some(defaultValue))), _, _, _, _, _)) =>
-              creator.withNullProvider(new NullValueProvider {
-                override def getNullValue(ctxt: DeserializationContext): AnyRef = defaultValue()
-
-                override def getNullAccessPattern: AccessPattern = AccessPattern.DYNAMIC
-              })
-            case _ => creator
+      Option(args) match {
+        case Some(array) => {
+          array.map {
+            case creator: CreatorProperty =>
+              // Locate the constructor param that matches it
+              descriptor.properties.find(_.param.exists(_.index == creator.getCreatorIndex)) match {
+                case Some(PropertyDescriptor(name, Some(ConstructorParameter(_, _, Some(defaultValue))), _, _, _, _, _)) =>
+                  creator.withNullProvider(new NullValueProvider {
+                    override def getNullValue(ctxt: DeserializationContext): AnyRef = defaultValue()
+
+                    override def getNullAccessPattern: AccessPattern = AccessPattern.DYNAMIC
+                  })
+                case _ => creator
+              }
+            case other => other
           }
-        case other => other
+        }
+        case _ => Array.empty
       }
     }
 

src/test/scala/com/fasterxml/jackson/module/scala/deser/CreatorTest.scala

@@ -39,11 +39,17 @@ object CreatorTest
     }
   }
 
+  sealed abstract class Struct1(val name: String, val classifier: String = "my_default_string") {
+    override def toString: String = name
+  }
+
   case class ConstructorWithDefaultValues(s: String = "some string", i: Int = 10, dummy: String)
 
   case class ConstructorWithOptionDefaultValues(s: Option[String] = None, i: Option[Int] = None, dummy: String)
 
   case class ConstructorWithOptionSeqDefaultValues(s: Option[Seq[String]] = None)
+
+  case class ConstructorWithOptionStruct(s: Option[Struct1] = None)
 }
 
 
@@ -140,4 +146,12 @@ class CreatorTest extends DeserializationFixture {
     deser2.s shouldEqual Some(Seq("a", "b"))
     f.writeValueAsString(ConstructorWithOptionSeqDefaultValues()) shouldEqual """{"s":null}"""
   }
+
+  it should "support optional structs with default values" ignore { f =>
+    val deser = f.readValue[ConstructorWithOptionStruct]("""{}""")
+    deser.s shouldBe empty
+    val deser2 = f.readValue[ConstructorWithOptionStruct]("""{"s":{"name":"name"}}""")
+    deser2.s shouldEqual Some(new Struct1("name"){})
+    f.writeValueAsString(ConstructorWithOptionStruct()) shouldEqual """{"s":null}"""
+  }
 }