Fix #2527

Author: cowtowncoder

release-notes/VERSION-2.x

@@ -24,6 +24,8 @@ Project: jackson-databind
 #2522: `DeserializationContext.handleMissingInstantiator()` throws `MismatchedInputException`
   for non-static inner classes
 #2525: Incorrect `JsonStreamContext` for `TokenBuffer` and `TreeTraversingParser`
+#2527: Add `AnnotationIntrospector.findRenameByField()` to support Kotlin's "is-getter"
+  naming convention
 #2555: Use `@JsonProperty(index)` for sorting properties on serialization
 #2565: Java 8 `Optional` not working with `@JsonUnwrapped` on unwrappable type
  (reported by Haowei W)

src/main/java/com/fasterxml/jackson/databind/introspect/POJOPropertiesCollector.java

@@ -89,6 +89,22 @@ public class POJOPropertiesCollector
     protected LinkedHashMap<String, POJOPropertyBuilder> _properties;
 
     protected LinkedList<POJOPropertyBuilder> _creatorProperties;
+
+    /**
+     * A set of "field renamings" that have been discovered, indicating
+     * intended renaming of other accesors: key is the implicit original
+     * name and value intended name to use instead.
+     *<p>
+     * Note that these renamings are applied earlier than "regular" (explicit)
+     * renamings and affect implicit name: their effect may be changed by
+     * further renaming based on explicit indicators.
+     * The main use case is to effectively relink accessors based on fields
+     * discovered, and used to sort of correct otherwise missing linkage between
+     * fields and other accessors.
+     *
+     * @since 2.11
+     */
+    protected Map<PropertyName, PropertyName> _fieldRenameMappings;
 
     protected LinkedList<AnnotatedMember> _anyGetters;
 
@@ -305,7 +321,7 @@ protected void collectAll()
         LinkedHashMap<String, POJOPropertyBuilder> props = new LinkedHashMap<String, POJOPropertyBuilder>();
 
         // First: gather basic data
-        _addFields(props);
+        _addFields(props); // note: populates _fieldRenameMappings
         _addMethods(props);
         // 25-Jan-2016, tatu: Avoid introspecting (constructor-)creators for non-static
         //    inner classes, see [databind#1502]
@@ -314,9 +330,6 @@ protected void collectAll()
         }
         _addInjectables(props);
 
-        // 27-Dec-2019, tatu: [databind#2527] initial re-linking by Field needs to
-        //    be applied before other processing
-        
         // Remove ignored properties, first; this MUST precede annotation merging
         // since logic relies on knowing exactly which accessor has which annotation
         _removeUnwantedProperties(props);
@@ -397,15 +410,20 @@ protected void _addFields(Map<String, POJOPropertyBuilder> props)
             if (implName == null) {
                 implName = f.getName();
             }
+            final PropertyName implNameP = _propNameFromSimple(implName);
 
             // [databind#2527: Field-based renaming can be applied early (here),
             // or at a later point, but probably must be done before pruning
             // final fields. So let's do it early here
-            final PropertyName rename = ai.findRenameByField(_config, f, _propNameFromSimple(implName));
-            if (rename != null) {
+            final PropertyName rename = ai.findRenameByField(_config, f, implNameP);
+            if ((rename != null) && !rename.equals(implNameP)) {
+                if (_fieldRenameMappings == null) {
+                    _fieldRenameMappings = new HashMap<>();
+                }
+                _fieldRenameMappings.put(rename, implNameP);
                 // todo
             }
-            
+
             PropertyName pn;
 
             if (_forSerialization) {
@@ -511,9 +529,12 @@ protected void _addCreatorParam(Map<String, POJOPropertyBuilder> props,
             pn = PropertyName.construct(impl);
         }
 
+        // 27-Dec-2019, tatu: [databind#2527] may need to rename according to field
+        impl = _checkRenameByField(impl);
+
         // shouldn't need to worry about @JsonIgnore, since creators only added
         // if so annotated
-
+        
         /* 13-May-2015, tatu: We should try to start with implicit name, similar to how
          *   fields and methods work; but unlike those, we don't necessarily have
          *   implicit name to use (pre-Java8 at least). So:
@@ -531,11 +552,11 @@ protected void _addMethods(Map<String, POJOPropertyBuilder> props)
     {
         final AnnotationIntrospector ai = _annotationIntrospector;
         for (AnnotatedMethod m : _classDef.memberMethods()) {
-            /* For methods, handling differs between getters and setters; and
-             * we will also only consider entries that either follow the bean
-             * naming convention or are explicitly marked: just being visible
-             * is not enough (unlike with fields)
-             */
+            // For methods, handling differs between getters and setters; and
+            // we will also only consider entries that either follow the bean
+            // naming convention or are explicitly marked: just being visible
+            // is not enough (unlike with fields)
+
             int argCount = m.getParameterCount();
             if (argCount == 0) { // getters (including 'any getter')
             	_addGetterMethod(props, m, ai);
@@ -616,6 +637,8 @@ protected void _addGetterMethod(Map<String, POJOPropertyBuilder> props,
             }
             visible = true;
         }
+        // 27-Dec-2019, tatu: [databind#2527] may need to rename according to field
+        implName = _checkRenameByField(implName);
         boolean ignore = ai.hasIgnoreMarker(m);
         _property(props, implName).addGetter(m, pn, nameExplicit, visible, ignore);
     }
@@ -653,6 +676,8 @@ protected void _addSetterMethod(Map<String, POJOPropertyBuilder> props,
             }
             visible = true;
         }
+        // 27-Dec-2019, tatu: [databind#2527] may need to rename according to field
+        implName = _checkRenameByField(implName);
         boolean ignore = (ai == null) ? false : ai.hasIgnoreMarker(m);
         _property(props, implName).addSetter(m, pn, nameExplicit, visible, ignore);
     }
@@ -697,7 +722,20 @@ protected void _doAddInjectable(JacksonInject.Value injectable, AnnotatedMember
     private PropertyName _propNameFromSimple(String simpleName) {
         return PropertyName.construct(simpleName, null);
     }
-    
+
+    // @since 2.11
+    private String _checkRenameByField(String implName) {
+        if (_fieldRenameMappings != null) {
+            PropertyName p = _fieldRenameMappings.get(_propNameFromSimple(implName));
+            if (p != null) {
+                implName = p.getSimpleName();
+                return implName;
+
+            }
+        }
+        return implName;
+    }
+
     /*
     /**********************************************************
     /* Internal methods; removing ignored properties

src/test/java/com/fasterxml/jackson/failing/IsGetterRenaming2527Test.java

@@ -3,6 +3,7 @@
 import java.util.Collections;
 import java.util.Map;
 
+import com.fasterxml.jackson.annotation.JsonProperty;
 import com.fasterxml.jackson.databind.*;
 import com.fasterxml.jackson.databind.cfg.MapperConfig;
 import com.fasterxml.jackson.databind.introspect.AnnotatedField;
@@ -24,18 +25,28 @@ public POJO2527(boolean b) {
         public void setEnabled(boolean b) { isEnabled = b; }
     }
 
-    static class POJO2527b {
+    static class POJO2527PublicField {
         public boolean isEnabled;
 
-        protected POJO2527b() { }
-        public POJO2527b(boolean b) {
+        protected POJO2527PublicField() { }
+        public POJO2527PublicField(boolean b) {
             isEnabled = b;
         }
 
         public boolean getEnabled() { return isEnabled; }
         public void setEnabled(boolean b) { isEnabled = b; }
     }
-    
+
+    static class POJO2527Creator {
+        private final boolean isEnabled;
+
+        public POJO2527Creator(@JsonProperty("enabled") boolean b) {
+            isEnabled = b;
+        }
+
+        public boolean getEnabled() { return isEnabled; }
+    }
+
     @SuppressWarnings("serial")
     static class MyIntrospector extends JacksonAnnotationIntrospector
     {
@@ -55,7 +66,9 @@ public PropertyName findRenameByField(MapperConfig<?> config,
         }
     }
 
-    private final ObjectMapper MAPPER = newJsonMapper();
+    private final ObjectMapper MAPPER = jsonMapperBuilder()
+            .annotationIntrospector(new MyIntrospector())
+            .build();
 
     public void testIsPropertiesStdKotlin() throws Exception
     {
@@ -70,16 +83,29 @@ public void testIsPropertiesStdKotlin() throws Exception
         assertEquals(input.isEnabled, output.isEnabled);
     }
 
-    public void testIsPropertiesAlt() throws Exception
+    public void testIsPropertiesWithPublicField() throws Exception
+    {
+        POJO2527PublicField input = new POJO2527PublicField(true);
+        final String json = MAPPER.writeValueAsString(input);
+
+        Map<?, ?> props = MAPPER.readValue(json, Map.class);
+        assertEquals(Collections.singletonMap("isEnabled", Boolean.TRUE),
+                props);
+        
+        POJO2527PublicField output = MAPPER.readValue(json, POJO2527PublicField.class);
+        assertEquals(input.isEnabled, output.isEnabled);
+    }
+
+    public void testIsPropertiesViaCreator() throws Exception
     {
-        POJO2527b input = new POJO2527b(true);
+        POJO2527Creator input = new POJO2527Creator(true);
         final String json = MAPPER.writeValueAsString(input);
 
         Map<?, ?> props = MAPPER.readValue(json, Map.class);
         assertEquals(Collections.singletonMap("isEnabled", Boolean.TRUE),
                 props);
 
-        POJO2527b output = MAPPER.readValue(json, POJO2527b.class);
+        POJO2527Creator output = MAPPER.readValue(json, POJO2527Creator.class);
         assertEquals(input.isEnabled, output.isEnabled);
     }
 }