Fixed #2280

Author: cowtowncoder

release-notes/CREDITS-2.x

@@ -756,7 +756,9 @@ Joe Schafer (jschaf@github)
 Deblock Thomas (deblockt@github)
   * Reported, contributed fix for #1912: `BeanDeserializerModifier.updateBuilder()` does not
     work to set custom  deserializer on a property (since 2.9.0)
- (contributed by Deblock T)
+   (2.9.5)
+  * Reported, suggested fix for #2280: JsonMerge not work with constructor args
+   (2.10.0)
 
 [email protected]:
   * Reported #1931: Two more `c3p0` gadgets to exploit default typing issue

release-notes/VERSION-2.x

@@ -42,6 +42,8 @@ Project: jackson-databind
 #2251: Getter that returns an abstract collection breaks a delegating `@JsonCreator`
 #2265: Inconsistent handling of Collections$UnmodifiableList vs Collections$UnmodifiableRandomAccessListq
 #2273: Add basic Java 9+ module info
+#2280: JsonMerge not work with constructor args
+ (reported by Deblock T)
 #2311: Unnecessary MultiView creation for property writers
  (suggested by Manuel H)
 #2338: Suboptimal return type for `JsonNode.withArray()`

src/main/java/com/fasterxml/jackson/databind/deser/CreatorProperty.java

@@ -253,7 +253,20 @@ public Object setAndReturn(Object instance, Object value) throws IOException
         _verifySetter();
         return _fallbackSetter.setAndReturn(instance, value);
     }
-    
+
+    @Override
+    public PropertyMetadata getMetadata() {
+        // 03-Jun-2019, tatu: Added as per [databind#2280] to support merge.
+        //   Not 100% sure why it would be needed (or fixes things) but... appears to.
+        //   Need to understand better in future as it seems like it should probably be
+        //   linked earlier during construction or something.
+        PropertyMetadata md = super.getMetadata();
+        if (_fallbackSetter != null) {
+            return md.withMergeInfo(_fallbackSetter.getMetadata().getMergeInfo());
+        }
+        return md;
+    }
+
     @Override
     public Object getInjectableValueId() {
         return _injectableValueId;

src/test/java/com/fasterxml/jackson/databind/deser/merge/PropertyMergeTest.java

@@ -87,6 +87,26 @@ static class CantMergeInts {
         public int value;
     }
 
+    // [databind#2280]
+    static class ConstructorArgsPojo {
+        static class MergeablePojo {
+            public String foo;
+            public String bar;
+
+            public MergeablePojo(String foo, String bar) {
+                this.foo = foo;
+                this.bar = bar;
+            }
+        }
+
+        public MergeablePojo mergeableBean;
+
+        @JsonCreator
+        public ConstructorArgsPojo(@JsonMerge @JsonProperty("mergeableBean") MergeablePojo mergeableBean) {
+            this.mergeableBean = mergeableBean;
+        }
+    }
+
     /*
     /********************************************************
     /* Test methods, POJO merging
@@ -153,6 +173,24 @@ public void testBeanMergingWithoutSetter() throws Exception
         assertEquals(1, config._value.a);
     }
 
+    /*
+    /********************************************************
+    /* Test methods, Creators
+    /********************************************************
+     */
+
+    // [databind#2280]
+    public void testBeanMergeUsingConstructors() throws Exception {
+        ConstructorArgsPojo input = new ConstructorArgsPojo(new ConstructorArgsPojo.MergeablePojo("foo", "bar"));
+
+        ConstructorArgsPojo result = MAPPER.setDefaultMergeable(true)
+                .readerForUpdating(input)
+                .readValue(aposToQuotes("{'mergeableBean': {'foo': 'newFoo'}}"));
+
+        assertEquals("newFoo", result.mergeableBean.foo);
+        assertEquals("bar", result.mergeableBean.bar);
+    }
+
     /*
     /********************************************************
     /* Test methods, as array