Add DeserializationFeature.FAIL_ON_MISSING_EXTERNAL_TYPE_ID_PROPERTY

src/main/java/com/fasterxml/jackson/databind/DeserializationFeature.java

@@ -244,6 +244,17 @@ public enum DeserializationFeature implements ConfigFeature
       */
     FAIL_ON_NULL_CREATOR_PROPERTIES(false),
 
+    /**
+     * Feature that determines what happens when a property annotated with
+     * {@link com.fasterxml.jackson.annotation.JsonTypeInfo.As#EXTERNAL_PROPERTY} is missing.
+     * This is disabled by default, so that no error is thrown when a subtype property is
+     * missing, unless the property is explicitly marked as `required`. If it is enabled, or
+     * the property is marked as 'required' then a {@link JsonMappingException} will be thrown.
+     *
+     * @since 2.8
+     */
+    FAIL_ON_EXTERNAL_TYPE_ID_MISSING_PROPERTY(false),
+
     /**
      * Feature that determines whether Jackson code should catch
      * and wrap {@link Exception}s (but never {@link Error}s!)

src/main/java/com/fasterxml/jackson/databind/deser/impl/ExternalTypeHandler.java

@@ -165,8 +165,13 @@ public Object complete(JsonParser p, DeserializationContext ctxt, Object bean)
                 }
             } else if (_tokens[i] == null) {
                 SettableBeanProperty prop = _properties[i].getProperty();
-                ctxt.reportMappingException("Missing property '%s' for external type id '%s'",
-                        prop.getName(), _properties[i].getTypePropertyName());
+
+                if(prop.isRequired() ||
+                        ctxt.isEnabled(DeserializationFeature.FAIL_ON_EXTERNAL_TYPE_ID_MISSING_PROPERTY)) {
+                    ctxt.reportMappingException("Missing property '%s' for external type id '%s'",
+                            prop.getName(), _properties[i].getTypePropertyName());
+                }
+                return bean;
             }
             _deserializeAndSet(p, ctxt, bean, i, typeId);
         }

src/test/java/com/fasterxml/jackson/databind/jsontype/TestSubtypesExternalPropertyMissingProperty.java

@@ -0,0 +1,262 @@
+package com.fasterxml.jackson.databind.jsontype;
+
+import com.fasterxml.jackson.annotation.JsonProperty;
+import com.fasterxml.jackson.annotation.JsonSubTypes;
+import com.fasterxml.jackson.annotation.JsonSubTypes.Type;
+import com.fasterxml.jackson.annotation.JsonTypeInfo;
+import com.fasterxml.jackson.annotation.JsonTypeInfo.As;
+import com.fasterxml.jackson.annotation.JsonTypeInfo.Id;
+import com.fasterxml.jackson.databind.BaseMapTest;
+import com.fasterxml.jackson.databind.DeserializationFeature;
+import com.fasterxml.jackson.databind.JsonMappingException;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.ExpectedException;
+
+import java.io.IOException;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertSame;
+
+public class TestSubtypesExternalPropertyMissingProperty {
+    @Rule
+    public ExpectedException thrown = ExpectedException.none();
+
+    /**
+     * Base class - external property for Fruit subclasses.
+     */
+    static class Box {
+        public String type;
+        @JsonTypeInfo(use = Id.NAME, include = As.EXTERNAL_PROPERTY, property = "type")
+        public Fruit fruit;
+
+        public Box() {
+        }
+
+        public Box(String type, Fruit fruit) {
+            this.type = type;
+            this.fruit = fruit;
+        }
+    }
+
+    /**
+     * Base class that requires the property to be present.
+     */
+    static class ReqBox {
+        public String type;
+        @JsonTypeInfo(use = Id.NAME, include = As.EXTERNAL_PROPERTY, property = "type")
+        @JsonProperty(required = true)
+        public Fruit fruit;
+
+        public ReqBox() {
+        }
+
+        public ReqBox(String type, Fruit fruit) {
+            this.type = type;
+            this.fruit = fruit;
+        }
+    }
+
+    @JsonSubTypes({
+            @Type(value = Apple.class, name = "apple"),
+            @Type(value = Orange.class, name = "orange")
+    })
+    static abstract class Fruit {
+        public String name;
+
+        public Fruit() {
+        }
+
+        protected Fruit(String n) {
+            name = n;
+        }
+    }
+
+    static class Apple extends Fruit {
+        public int seedCount;
+
+        public Apple() {
+        }
+
+        public Apple(String name, int b) {
+            super(name);
+            seedCount = b;
+        }
+    }
+
+    static class Orange extends Fruit {
+        public String color;
+
+        public Orange() {
+        }
+
+        public Orange(String name, String c) {
+            super(name);
+            color = c;
+        }
+    }
+
+    private final ObjectMapper MAPPER = new ObjectMapper();
+
+    /*
+    /**********************************************************
+    /* Mock data
+    /**********************************************************
+     */
+
+    private static final Orange orange = new Orange("Orange", "orange");
+    private static final Box orangeBox = new Box("orange", orange);
+    private static final String orangeBoxJson = "{\"type\":\"orange\",\"fruit\":{\"name\":\"Orange\",\"color\":\"orange\"}}";
+    private static final String orangeBoxNullJson = "{\"type\":\"orange\",\"fruit\":null}}";
+    private static final String orangeBoxEmptyJson = "{\"type\":\"orange\",\"fruit\":{}}}";
+    private static final String orangeBoxMissingJson = "{\"type\":\"orange\"}}";
+
+    private static final Apple apple = new Apple("Apple", 16);
+    private static Box appleBox = new Box("apple", apple);
+    private static final String appleBoxJson = "{\"type\":\"apple\",\"fruit\":{\"name\":\"Apple\",\"seedCount\":16}}";
+    private static final String appleBoxNullJson = "{\"type\":\"apple\",\"fruit\":null}";
+    private static final String appleBoxEmptyJson = "{\"type\":\"apple\",\"fruit\":{}}";
+    private static final String appleBoxMissingJson = "{\"type\":\"apple\"}";
+
+    /*
+    /**********************************************************
+    /* Unit tests
+    /**********************************************************
+     */
+
+    /**
+     * Deserialization tests for external type id property present
+     */
+    @Test
+    public void testDeserializationPresent() throws Exception {
+        MAPPER.disable(DeserializationFeature.FAIL_ON_EXTERNAL_TYPE_ID_MISSING_PROPERTY);
+        checkOrangeBox();
+        checkAppleBox();
+
+        MAPPER.enable(DeserializationFeature.FAIL_ON_EXTERNAL_TYPE_ID_MISSING_PROPERTY);
+        checkOrangeBox();
+        checkAppleBox();
+    }
+
+    /**
+     * Deserialization tests for external type id property null
+     */
+    @Test
+    public void testDeserializationNull() throws Exception {
+        MAPPER.disable(DeserializationFeature.FAIL_ON_EXTERNAL_TYPE_ID_MISSING_PROPERTY);
+        checkOrangeBoxNull(orangeBoxNullJson);
+        checkAppleBoxNull(appleBoxNullJson);
+
+        MAPPER.enable(DeserializationFeature.FAIL_ON_EXTERNAL_TYPE_ID_MISSING_PROPERTY);
+        checkOrangeBoxNull(orangeBoxNullJson);
+        checkAppleBoxNull(appleBoxNullJson);
+    }
+
+    /**
+     * Deserialization tests for external type id property empty
+     */
+    @Test
+    public void testDeserializationEmpty() throws Exception {
+        MAPPER.disable(DeserializationFeature.FAIL_ON_EXTERNAL_TYPE_ID_MISSING_PROPERTY);
+        checkOrangeBoxEmpty(orangeBoxEmptyJson);
+        checkAppleBoxEmpty(appleBoxEmptyJson);
+
+        MAPPER.enable(DeserializationFeature.FAIL_ON_EXTERNAL_TYPE_ID_MISSING_PROPERTY);
+        checkOrangeBoxEmpty(orangeBoxEmptyJson);
+        checkAppleBoxEmpty(appleBoxEmptyJson);
+    }
+
+    /**
+     * Deserialization tests for external type id property missing
+     */
+    @Test
+    public void testDeserializationMissing() throws Exception {
+        MAPPER.disable(DeserializationFeature.FAIL_ON_EXTERNAL_TYPE_ID_MISSING_PROPERTY);
+        checkOrangeBoxNull(orangeBoxMissingJson);
+        checkAppleBoxNull(appleBoxMissingJson);
+
+        MAPPER.enable(DeserializationFeature.FAIL_ON_EXTERNAL_TYPE_ID_MISSING_PROPERTY);
+        checkBoxJsonMappingException(orangeBoxMissingJson);
+        checkBoxJsonMappingException(appleBoxMissingJson);
+    }
+
+    /**
+     * Deserialization tests for external type id required property missing
+     */
+    @Test
+    public void testDeserializationMissingRequired() throws Exception {
+        MAPPER.disable(DeserializationFeature.FAIL_ON_EXTERNAL_TYPE_ID_MISSING_PROPERTY);
+        checkReqBoxJsonMappingException(orangeBoxMissingJson);
+        checkReqBoxJsonMappingException(appleBoxMissingJson);
+
+        MAPPER.enable(DeserializationFeature.FAIL_ON_EXTERNAL_TYPE_ID_MISSING_PROPERTY);
+        checkReqBoxJsonMappingException(orangeBoxMissingJson);
+        checkReqBoxJsonMappingException(appleBoxMissingJson);
+    }
+
+    private void checkOrangeBox() throws Exception {
+        Box deserOrangeBox = MAPPER.readValue(orangeBoxJson, Box.class);
+        assertEquals(orangeBox.type, deserOrangeBox.type);
+
+        Fruit deserOrange = deserOrangeBox.fruit;
+        assertSame(Orange.class, deserOrange.getClass());
+        assertEquals(orange.name, deserOrange.name);
+        assertEquals(orange.color, ((Orange) deserOrange).color);
+    }
+
+    private void checkAppleBox() throws Exception {
+        Box deserAppleBox = MAPPER.readValue(appleBoxJson, Box.class);
+        assertEquals(appleBox.type, deserAppleBox.type);
+
+        Fruit deserApple = deserAppleBox.fruit;
+        assertSame(Apple.class, deserApple.getClass());
+        assertEquals(apple.name, deserApple.name);
+        assertEquals(apple.seedCount, ((Apple) deserApple).seedCount);
+    }
+
+    private void checkOrangeBoxEmpty(String json) throws Exception {
+        Box deserOrangeBox = MAPPER.readValue(json, Box.class);
+        assertEquals(orangeBox.type, deserOrangeBox.type);
+
+        Fruit deserOrange = deserOrangeBox.fruit;
+        assertSame(Orange.class, deserOrange.getClass());
+        assertNull(deserOrange.name);
+        assertNull(((Orange) deserOrange).color);
+    }
+
+    private void checkAppleBoxEmpty(String json) throws Exception {
+        Box deserAppleBox = MAPPER.readValue(json, Box.class);
+        assertEquals(appleBox.type, deserAppleBox.type);
+
+        Fruit deserApple = deserAppleBox.fruit;
+        assertSame(Apple.class, deserApple.getClass());
+        assertNull(deserApple.name);
+        assertEquals(0, ((Apple) deserApple).seedCount);
+    }
+
+    private void checkOrangeBoxNull(String json) throws Exception {
+        Box deserOrangeBox = MAPPER.readValue(json, Box.class);
+        assertEquals(orangeBox.type, deserOrangeBox.type);
+        assertNull(deserOrangeBox.fruit);
+    }
+
+    private void checkAppleBoxNull(String json) throws Exception {
+        Box deserAppleBox = MAPPER.readValue(json, Box.class);
+        assertEquals(appleBox.type, deserAppleBox.type);
+        assertNull(deserAppleBox.fruit);
+    }
+
+    private void checkBoxJsonMappingException(String json) throws Exception {
+        thrown.expect(JsonMappingException.class);
+        thrown.expectMessage("Missing property 'fruit' for external type id 'type'");
+        MAPPER.readValue(json, Box.class);
+    }
+
+    private void checkReqBoxJsonMappingException(String json) throws Exception {
+        thrown.expect(JsonMappingException.class);
+        thrown.expectMessage("Missing property 'fruit' for external type id 'type'");
+        MAPPER.readValue(json, ReqBox.class);
+    }
+}