check added to prevent IonValue null deserialization to fail when bean has a missing property (#322)

Author: atokuzAmzn

ion/src/main/java/com/fasterxml/jackson/dataformat/ion/ionvalue/IonValueDeserializer.java

@@ -17,6 +17,7 @@
 import java.io.IOException;
 
 import com.fasterxml.jackson.core.JsonParser;
+import com.fasterxml.jackson.core.JsonToken;
 import com.fasterxml.jackson.databind.DeserializationContext;
 import com.fasterxml.jackson.databind.JsonMappingException;
 import com.fasterxml.jackson.databind.JsonDeserializer;
@@ -58,11 +59,14 @@ public IonValue deserialize(JsonParser jp, DeserializationContext ctxt) throws I
     @Override
     public IonValue getNullValue(DeserializationContext ctxt) throws JsonMappingException {
         try {
-            Object embeddedObj = ctxt.getParser().getEmbeddedObject();
-            if (embeddedObj instanceof IonValue) {
-                IonValue iv = (IonValue) embeddedObj;
-                if (iv.isNullValue()) {
-                    return iv;
+            final JsonParser parser = ctxt.getParser();
+            if (parser != null && parser.getCurrentToken() != JsonToken.END_OBJECT) {
+                final Object embeddedObj = parser.getEmbeddedObject();
+                if (embeddedObj instanceof IonValue) {
+                    IonValue iv = (IonValue) embeddedObj;
+                    if (iv.isNullValue()) {
+                        return iv;
+                    }
                 }
             }
 

ion/src/test/java/com/fasterxml/jackson/dataformat/ion/ionvalue/IonValueDeserializerTest.java

@@ -2,12 +2,16 @@
 
 import com.amazon.ion.IonSystem;
 import com.amazon.ion.IonValue;
+import com.amazon.ion.IonStruct;
 import com.amazon.ion.system.IonSystemBuilder;
 import com.fasterxml.jackson.annotation.JsonAnyGetter;
 import com.fasterxml.jackson.annotation.JsonAnySetter;
+import com.fasterxml.jackson.annotation.JsonProperty;
 import com.fasterxml.jackson.databind.util.AccessPattern;
+import com.fasterxml.jackson.dataformat.ion.IonObjectMapper;
 import org.junit.Test;
 
+import java.io.IOException;
 import java.util.HashMap;
 import java.util.Map;
 import java.util.Objects;
@@ -166,6 +170,39 @@ public void shouldBeAbleToSerializeAndDeserializeStringData() throws Exception {
         assertEquals(source, result);
     }
 
+    static class MyBean {
+        public IonStruct required;
+        public IonStruct optional;
+
+        MyBean(
+            @JsonProperty("required") IonStruct required,
+            @JsonProperty("optional") IonStruct optional
+        ) {
+            this.required = required;
+            this.optional = optional;
+        }
+    }
+
+    @Test
+    public void testWithMissingProperty() throws IOException
+    {
+        IonSystem ionSystem = IonSystemBuilder.standard().build();
+        IonObjectMapper ionObjectMapper = IonObjectMapper.builder(ionSystem)
+            .addModule(new IonValueModule())
+            .build();
+
+        String input1 = "{required:{}, optional:{}}";
+        MyBean deserializedBean1 = ionObjectMapper.readValue(input1, MyBean.class);
+        assertEquals(ionSystem.newEmptyStruct(), deserializedBean1.required);
+        assertEquals(ionSystem.newEmptyStruct(), deserializedBean1.optional);
+
+        // This deserialization should not fail with missing property
+        String input2 = "{required:{}}";
+        MyBean deserializedBean2 = ionObjectMapper.readValue(input2, MyBean.class);
+        assertEquals(ionSystem.newEmptyStruct(), deserializedBean2.required);
+        assertEquals(null, deserializedBean2.optional);
+    }
+
     @Test
     public void shouldOverrideNullAccessPatternToBeDynamic() {
         IonValueDeserializer deserializer = new IonValueDeserializer();