Fix #5405: @JsonFormat(shape = Shape.POJO) does not work for java.util.Map serialization via property annotation

release-notes/CREDITS

@@ -125,10 +125,13 @@ Oliver Drotbohm (@odrotbohm)
 
 @JacksonJang
  * Contributed fix for #4629: `@JsonIncludeProperties` and `@JsonIgnoreProperties`
-  ignored when deserializing Records
+   ignored when deserializing Records
   [3.1.0]
  * Contributed fix for #5115: `@JsonUnwrapped` Record deserialization can't handle
-  name collision
+   name collision
+  [3.1.0]
+ * Contributed fix for #5405: `@JsonFormat(shape = Shape.POJO)` does not work for
+   `java.util.Map` serialization via property annotation
   [3.1.0]
 
 Viktor Szathmáry (@phraktle)

release-notes/VERSION

@@ -39,9 +39,12 @@ Versions: 3.x (for earlier see VERSION-2.x)
 #5361: Fix Maven SBOM publishing (worked in 3.0.0-rc4 but not in rc5 or later)
 (date-time)#359: `InstantDeserializer` deserializes the nanosecond portion of
   fractional negative timestamps incorrectly
+#5405: `@JsonFormat(shape = Shape.POJO)` does not work for `java.util.Map`
+  serialization via property annotation
+ (fix contributed by @JacksonJang)
 #5413: Add/support forward reference resolution for array values
  (contributed by Hélios G)
-5442: Make `JsonMapper/ObjectMapper` fully proxyable by CGLIB
+#5442: Make `JsonMapper/ObjectMapper` fully proxyable by CGLIB
  (fix contributed by Fouad A)
 #5456: Additional configuration (`JsonNodeFeature.STRIP_TRAILING_BIGDECIMAL_ZEROES`: true)
   to MapperBuilder#configureForJackson2 to closer match Jackson 2 behavior

src/main/java/tools/jackson/databind/SerializationContext.java

@@ -695,6 +695,10 @@ public ValueSerializer<Object> findPrimaryPropertySerializer(JavaType valueType,
         ValueSerializer<Object> ser = _knownSerializers.untypedValueSerializer(valueType);
         if (ser == null) {
             ser = _createAndCachePropertySerializer(valueType, property);
+        } else if (property != null) {
+            BeanDescription.Supplier beanDescRef = lazyIntrospectBeanDescription(valueType);
+            // [databind#5405]: property-level @JsonFormat must be honored even with cached serializers
+            ser = _checkShapeShifting(valueType, beanDescRef, property, ser);
         }
         return handlePrimaryContextualization(ser, property);
     }
@@ -705,14 +709,26 @@ public ValueSerializer<Object> findPrimaryPropertySerializer(JavaType valueType,
     public ValueSerializer<Object> findPrimaryPropertySerializer(Class<?> rawType,
             BeanProperty property)
     {
+        boolean checkShape = (property != null);
+        JavaType fullType = null;
+
         ValueSerializer<Object> ser = _knownSerializers.untypedValueSerializer(rawType);
         if (ser == null) {
-            JavaType fullType = _config.constructType(rawType);
+            fullType = _config.constructType(rawType);
             ser = _serializerCache.untypedValueSerializer(fullType);
             if (ser == null) {
+                checkShape = false; // because next call does it
                 ser = _createAndCachePropertySerializer(rawType, fullType, property);
             }
         }
+        if (checkShape) {
+            if (fullType == null) {
+                fullType = _config.constructType(rawType);
+            }
+            BeanDescription.Supplier beanDescRef = lazyIntrospectBeanDescription(fullType);
+            // [databind#5405]: property-level @JsonFormat must be honored even with cached serializers
+            ser = _checkShapeShifting(fullType, beanDescRef, property, ser);
+        }
         return handlePrimaryContextualization(ser, property);
     }
 
@@ -1041,7 +1057,7 @@ private ValueSerializer<Object> _checkShapeShifting(JavaType type,
             BeanDescription.Supplier beanDescRef, BeanProperty prop, ValueSerializer<?> ser)
     {
         JsonFormat.Value overrides = prop.findFormatOverrides(_config);
-        if (overrides != null) {
+        if (overrides != null && overrides != JsonFormat.Value.empty()) {
             // First: it may be completely fine to use serializer, despite some overrides
             ValueSerializer<?> ser2 = ser.withFormatOverrides(_config, overrides);
             if (ser2 != null) {

src/test/java/tools/jackson/databind/tofix/MapFormatShape5405Test.java → src/test/java/tools/jackson/databind/format/MapFormatShape5405Test.java

@@ -1,4 +1,4 @@
-package tools.jackson.databind.tofix;
+package tools.jackson.databind.format;
 
 import java.util.*;
 
@@ -8,9 +8,8 @@
 import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
-import tools.jackson.databind.*;
+import tools.jackson.databind.ObjectMapper;
 import tools.jackson.databind.testutil.DatabindTestUtil;
-import tools.jackson.databind.testutil.failure.JacksonTestFailureExpected;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
@@ -72,9 +71,20 @@ public Bean5405Override(int value) {
     // [databind#5045]: property overrides for @JsonFormat.shape won't work for Maps
     // 30-Nov-2025, tatu: Something about caching is the issue: if "b" commented out,
     //    override appears to work; with "b" not
-    @JacksonTestFailureExpected
     @Test
     public void serializeAsPOJOViaProperty() throws Exception
+    {
+        String result = MAPPER.writeValueAsString(new Bean5405Container(1,0,3));
+        assertEquals(a2q(
+                "{'a':{'extra':13,'empty':false},'c':{'extra':13,'empty':false}}"),
+                result);
+    }
+
+    // [databind#5405]:
+    // 01-Dec-2025, JacksonJang: In this case, the @JsonFormat(shape = POJO) override
+    // behaves correctly even with b included.
+    @Test
+    public void serializeAsPOJOViaFullProperty() throws Exception
     {
         String result = MAPPER.writeValueAsString(new Bean5405Container(1,2,3));
         assertEquals(a2q(