Fix #727

Author: cowtowncoder

release-notes/VERSION

@@ -13,6 +13,7 @@ Project: jackson-databind
 #700: Cannot Change Default Abstract Type Mapper from LinkedHashMap
  (reported by wealdtech@github)
 #725: Auto-detect multi-argument constructor with implicit names if it is the only visible creator
+#727: Improve `ObjectWriter.forType()` to avoid forcing base type for container types
 - Remove old cglib compatibility tests; cause problems in Eclipse
 
 2.5.2 (not yet released)

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

@@ -449,11 +449,16 @@ public ObjectWriter forType(JavaType rootType)
             pf = Prefetch.empty;
         } else {
             // 15-Mar-2013, tatu: Important! Indicate that static typing is needed:
-            rootType = rootType.withStaticTyping();
+            /* 19-Mar-2015, tatu: Except when dealing with Collection, Map types, where
+             *    this does more harm than help.
+             */
+            if (!rootType.isContainerType()) {
+                rootType = rootType.withStaticTyping();
+            }
             pf = _prefetchRootSerializer(_config, rootType);
         }
         return (pf == _prefetch) ? this : _new(_generatorSettings, pf);
-    }    
+    }
 
     /**
      * Method that will construct a new instance that uses specific type

src/test/java/com/fasterxml/jackson/databind/ser/TestGenericTypes.java

@@ -2,18 +2,13 @@
 
 import java.util.*;
 
-
+import com.fasterxml.jackson.annotation.JsonPropertyOrder;
+import com.fasterxml.jackson.core.type.TypeReference;
 import com.fasterxml.jackson.databind.BaseMapTest;
 import com.fasterxml.jackson.databind.ObjectMapper;
 
 public class TestGenericTypes extends BaseMapTest
 {
-    /*
-    /**********************************************************
-    /* Helper types
-    /**********************************************************
-     */
-    
     static class Account {
         private Long id;        
         private String name;
@@ -90,25 +85,41 @@ class Element {
             public Element(T v) { value = v; }
         }
     }
+
+    // For [databind#728]
+    static class Base727 {
+        public int a;
+    }
 
+    @JsonPropertyOrder(alphabetic=true)
+    static class Impl727 extends Base727 {
+        public int b;
+
+        public Impl727(int a, int b) {
+            this.a = a;
+            this.b = b;
+        }
+    }    
     /*
     /**********************************************************
     /* Unit tests
     /**********************************************************
      */
 
+//    final ObjectMapper MAPPER = new ObjectMapper();
+    final ObjectMapper MAPPER = objectMapper();
+
     @SuppressWarnings("unchecked")
     public void testIssue468a() throws Exception
     {
         Person1 p1 = new Person1("John");
         p1.setAccount(new Key<Account>(new Account("something", 42L)));
 
         // First: ensure we can serialize (pre 1.7 this failed)
-        ObjectMapper mapper = new ObjectMapper();
-        String json = mapper.writeValueAsString(p1);
+        String json = MAPPER.writeValueAsString(p1);
 
         // and then verify that results make sense
-        Map<String,Object> map = mapper.readValue(json, Map.class);
+        Map<String,Object> map = MAPPER.readValue(json, Map.class);
         assertEquals("John", map.get("name"));
         Object ob = map.get("account");
         assertNotNull(ob);
@@ -131,11 +142,10 @@ public void testIssue468b() throws Exception
         p2.setAccounts(accounts);
 
         // serialize without error:
-        ObjectMapper mapper = new ObjectMapper();               
-        String json = mapper.writeValueAsString(p2);
+        String json = MAPPER.writeValueAsString(p2);
 
         // then verify output
-        Map<String,Object> map = mapper.readValue(json, Map.class);
+        Map<String,Object> map = MAPPER.readValue(json, Map.class);
         assertEquals("John", map.get("name"));
         Object ob = map.get("accounts");
         assertNotNull(ob);
@@ -145,14 +155,28 @@ public void testIssue468b() throws Exception
     }
 
     /**
-     * Issue [JACKSON-572] is about unbound type variables, usually resulting
+     * Test related to unbound type variables, usually resulting
      * from inner classes of generic classes (like Sets).
      */
-    public void testUnboundIssue572() throws Exception
+    public void testUnboundTypes() throws Exception
     {
         GenericBogusWrapper<Integer> list = new GenericBogusWrapper<Integer>(Integer.valueOf(7));
-        String json = new ObjectMapper().writeValueAsString(list);
+        String json = MAPPER.writeValueAsString(list);
         assertEquals("{\"wrapped\":{\"value\":7}}", json);
     }
-}
 
+    public void testRootTypeForCollections727() throws Exception
+    {
+        List<Base727> input = new ArrayList<Base727>();
+        input.add(new Impl727(1, 2));
+
+        final String EXP = aposToQuotes("[{'a':1,'b':2}]");
+        // Without type enforcement, produces expected output:
+        assertEquals(EXP, MAPPER.writeValueAsString(input));
+        assertEquals(EXP, MAPPER.writer().writeValueAsString(input));
+
+        // but enforcing type will hinder:
+        TypeReference<?> typeRef = new TypeReference<List<Base727>>() { };
+        assertEquals(EXP, MAPPER.writer().forType(typeRef).writeValueAsString(input));
+    }
+}

src/test/java/com/fasterxml/jackson/failing/TestPolymorphicDeserialization.java renamed to src/test/java/com/fasterxml/jackson/failing/TestPolymorphicDeserialization283.java

@@ -17,7 +17,7 @@
  * Whether this is wrong, and if so, can we fix it, is unknown at this point
  * (2.3): quite possibly this can not be changed.
  */
-public class TestPolymorphicDeserialization extends BaseMapTest
+public class TestPolymorphicDeserialization283 extends BaseMapTest
 {
     @JsonTypeInfo(use = JsonTypeInfo.Id.NAME, property = "type", defaultImpl = ClassA.class)
     @JsonSubTypes({