Fix #3063: resolve seeming @JsonValue conflict (useful with Records) (#3735)

Author: cowtowncoder

release-notes/CREDITS-2.x

@@ -1532,3 +1532,7 @@ Moritz Halbritter (mhalbritter@github)
 Philippe Marschall (marschall@github)
   * Contributed #3699: Allow custom `JsonNode` implementations
   (2.14.2)
+
+Gili Tzabari (cowwoc@github)
+  * Reported #3063: `@JsonValue` fails for Java Record
+  (2.14.2)

release-notes/VERSION-2.x

@@ -8,6 +8,8 @@ Project: jackson-databind
 
 #1751: `@JsonTypeInfo` does not work if the Type Id is an Integer value
  (reported by @marvin-we)
+#3063: `@JsonValue` fails for Java Record
+ (reported by Gili T)
 #3699: Allow custom `JsonNode` implementations
  (contributed by Philippe M)
 #3711: Enum polymorphism not working correctly with DEDUCTION

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

@@ -251,9 +251,11 @@ public AnnotatedMember getJsonKeyAccessor() {
         // If @JsonKey defined, must have a single one
         if (_jsonKeyAccessors != null) {
             if (_jsonKeyAccessors.size() > 1) {
-                reportProblem("Multiple 'as-key' properties defined (%s vs %s)",
-                        _jsonKeyAccessors.get(0),
-                        _jsonKeyAccessors.get(1));
+                if (!_resolveFieldVsGetter(_jsonKeyAccessors)) {
+                    reportProblem("Multiple 'as-key' properties defined (%s vs %s)",
+                            _jsonKeyAccessors.get(0),
+                            _jsonKeyAccessors.get(1));
+                }
             }
             // otherwise we won't greatly care
             return _jsonKeyAccessors.get(0);
@@ -270,11 +272,14 @@ public AnnotatedMember getJsonValueAccessor()
             collectAll();
         }
         // If @JsonValue defined, must have a single one
+        // 15-Jan-2023, tatu: Except let's try resolving "getter-over-field" case at least
         if (_jsonValueAccessors != null) {
             if (_jsonValueAccessors.size() > 1) {
-                reportProblem("Multiple 'as-value' properties defined (%s vs %s)",
-                        _jsonValueAccessors.get(0),
-                        _jsonValueAccessors.get(1));
+                if (!_resolveFieldVsGetter(_jsonValueAccessors)) {
+                    reportProblem("Multiple 'as-value' properties defined (%s vs %s)",
+                            _jsonValueAccessors.get(0),
+                            _jsonValueAccessors.get(1));
+                }
             }
             // otherwise we won't greatly care
             return _jsonValueAccessors.get(0);
@@ -1123,7 +1128,7 @@ protected void _renameWithWrappers(Map<String, POJOPropertyBuilder> props)
 
     /*
     /**********************************************************
-    /* Overridable internal methods, sorting, other stuff
+    /* Internal methods, sorting
     /**********************************************************
      */
 
@@ -1244,6 +1249,48 @@ private boolean _anyIndexed(Collection<POJOPropertyBuilder> props) {
         return false;
     }
 
+    /*
+    /**********************************************************
+    /* Internal methods, conflict resolution
+    /**********************************************************
+     */
+
+    /**
+     * Method that will be given a {@link List} with 2 or more accessors
+     * that may be in conflict: it will need to remove lower-priority accessors
+     * to leave just a single highest-priority accessor to use.
+     * If this succeeds method returns {@code true}, otherwise {@code false}.
+     *<p>
+     * NOTE: method will directly modify given {@code List} directly, regardless
+     * of whether it ultimately succeeds or not.
+     *
+     * @return True if seeming conflict was resolved and there only remains
+     *    single accessor
+     */
+    protected boolean _resolveFieldVsGetter(List<AnnotatedMember> accessors) {
+        do {
+            AnnotatedMember acc1 = accessors.get(0);
+            AnnotatedMember acc2 = accessors.get(1);
+
+            if (acc1 instanceof AnnotatedField) {
+                if (acc2 instanceof AnnotatedMethod) {
+                    // Method has precedence, remove first entry
+                    accessors.remove(0);
+                    continue;
+                }
+            } else if (acc1 instanceof AnnotatedMethod) {
+                // Method has precedence, remove second entry
+                if (acc2 instanceof AnnotatedField) {
+                    accessors.remove(1);
+                    continue;
+                }
+            }
+            // Not a field/method pair; fail
+            return false;
+        } while (accessors.size() > 1);
+        return true;
+    }
+
     /*
     /**********************************************************
     /* Internal methods; helpers

src/test-jdk14/java/com/fasterxml/jackson/databind/records/RecordJsonValue3063Test.java

@@ -0,0 +1,33 @@
+package com.fasterxml.jackson.databind.records;
+
+import java.util.Collections;
+import java.util.Map;
+
+import com.fasterxml.jackson.annotation.*;
+
+import com.fasterxml.jackson.databind.BaseMapTest;
+import com.fasterxml.jackson.databind.ObjectMapper;
+
+public class RecordJsonValue3063Test extends BaseMapTest
+{
+    // [databind#3063]
+    record GetLocations3063(@JsonValue Map<String, String> nameToLocation)
+    {
+         @JsonCreator
+         public GetLocations3063(Map<String, String> nameToLocation)
+         {
+              this.nameToLocation = nameToLocation;
+         }
+    }
+
+    private final ObjectMapper MAPPER = newJsonMapper();
+
+    // [databind#3063]
+    public void testRecordWithJsonValue3063() throws Exception
+    {
+        Map<String, String> locations = Collections.singletonMap("a", "locationA");
+        String json = MAPPER.writeValueAsString(new GetLocations3063(locations));
+
+        assertNotNull(json);
+    }
+}