Add failing test for #4742

src/test/java/com/fasterxml/jackson/databind/tofix/JacksonBuilderCreatorSubtype4742Test.java

@@ -0,0 +1,130 @@
+package com.fasterxml.jackson.databind.tofix;
+
+import java.util.List;
+
+import org.junit.jupiter.api.Test;
+
+import com.fasterxml.jackson.annotation.JsonCreator;
+import com.fasterxml.jackson.annotation.JsonProperty;
+import com.fasterxml.jackson.annotation.JsonSubTypes;
+import com.fasterxml.jackson.annotation.JsonTypeInfo;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.annotation.JsonDeserialize;
+import com.fasterxml.jackson.databind.testutil.DatabindTestUtil;
+import com.fasterxml.jackson.databind.testutil.failure.JacksonTestFailureExpected;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertInstanceOf;
+
+// [databind#4742] Deserialization with Builder, External type id,
+//                @JsonCreator not yet implemented
+public class JacksonBuilderCreatorSubtype4742Test
+        extends DatabindTestUtil
+{
+
+    public static class Animals {
+        @JsonProperty("animals")
+        public List<Animal> animals;
+    }
+
+    @JsonDeserialize(builder = Animal.Builder.class)
+    public static class Animal {
+        @JsonProperty("kind")
+        public String kind;
+
+        @JsonProperty("properties")
+        public AnimalProperties properties;
+
+        @Override
+        public String toString() {
+            return "Animal{kind='" + kind + '\'' + ", properties=" + properties + '}';
+        }
+
+        public static abstract class Builder {
+            @JsonProperty("kind")
+            public abstract Builder kind(String kind);
+
+            @JsonProperty("properties")
+            @JsonTypeInfo(use = JsonTypeInfo.Id.NAME, include = JsonTypeInfo.As.EXTERNAL_PROPERTY, property = "kind")
+            @JsonSubTypes({
+                    @JsonSubTypes.Type(name = "bird", value = BirdProperties.class),
+                    @JsonSubTypes.Type(name = "mammal", value = MammalProperties.class)
+            })
+            public abstract Builder properties(AnimalProperties properties);
+
+            @JsonCreator
+            public static BuilderImpl create() {
+                return new BuilderImpl();
+            }
+
+            public abstract Animal build();
+        }
+
+        public static class BuilderImpl extends Builder {
+            private String kind;
+            private AnimalProperties properties;
+
+            public BuilderImpl kind(String kind) {
+                this.kind = kind;
+                return this;
+            }
+
+            public BuilderImpl properties(AnimalProperties properties) {
+                this.properties = properties;
+                return this;
+            }
+
+            @Override
+            public Animal build() {
+                final Animal animal = new Animal();
+                animal.kind = kind;
+                animal.properties = properties;
+                return animal;
+            }
+        }
+    }
+
+    public interface AnimalProperties {
+    }
+
+    public static class MammalProperties implements AnimalProperties {
+        @JsonProperty("num_teeth")
+        public int teeth;
+
+        @Override
+        public String toString() {
+            return "MammalProperties{teeth=" + teeth + '}';
+        }
+    }
+
+    public static class BirdProperties implements AnimalProperties {
+        @JsonProperty("color")
+        public String color;
+
+        @Override
+        public String toString() {
+            return "BirdProperties{color='" + color + '\'' + '}';
+        }
+    }
+
+    final ObjectMapper MAPPER = newJsonMapper();
+
+    @JacksonTestFailureExpected
+    @Test
+    public void testDeser()
+            throws Exception
+    {
+        final Animals animals = MAPPER.readValue(
+                "{\n" +
+                        "  \"animals\": [\n" +
+                        "    {\"kind\": \"bird\", \"properties\": {\"color\": \"yellow\"}},\n" +
+                        "    {\"kind\": \"mammal\", \"properties\": {\"num_teeth\": 2}}\n" +
+                        "  ]\n" +
+                        "}", Animals.class);
+
+        assertEquals(2, animals.animals.size());
+        assertInstanceOf(BirdProperties.class, animals.animals.get(0).properties);
+        assertInstanceOf(MammalProperties.class, animals.animals.get(1).properties);
+
+    }
+}