Fix #3948: retain transient field for ignoral if annotated with `@J…

…sonIgnoral` (or similar) (#4048)

release-notes/CREDITS-2.x

@@ -1673,3 +1673,7 @@ iProdigy (iProdigy@github)
   (2.16.0)
  * Contributed fix #4041: Actually cache EnumValues#internalMap
   (2.16.0)
+
+Jason Laber (jlaber@github)
+ * Reported #3948: `@JsonIgnore` no longer works for transient backing fields
+  (2.16.0)

release-notes/VERSION-2.x

@@ -20,6 +20,8 @@ Project: jackson-databind
  (fix contributed by Joo-Hyuk K)
 #3928: `@JsonProperty` on constructor parameter changes default field serialization order
  (contributed by @pjfanning)
+#3948: `@JsonIgnore` no longer works for transient backing fields
+ (reported by Jason L)
 #3950: Create new `JavaType` subtype `IterationType` (extending `SimpleType`)
 #3953: Use `JsonTypeInfo.Value` for annotation handling
  (contributed by Joo-Hyuk K)

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

@@ -58,6 +58,10 @@ public enum MapperFeature implements ConfigFeature
      * Feature is disabled by default, meaning that existence of `transient`
      * for a field does not necessarily lead to ignoral of getters or setters
      * but just ignoring the use of field for access.
+     *<p>
+     * NOTE! This should have no effect on <b>explicit</b> ignoral annotation
+     * possibly added to {@code transient} fields: those should always have expected
+     * semantics (same as if field was not {@code transient}).
      *
      * @since 2.6
      */

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

@@ -612,7 +612,10 @@ protected void _addFields(Map<String, POJOPropertyBuilder> props)
                     //     only retain if also have ignoral annotations (for name or ignoral)
                     if (transientAsIgnoral) {
                         ignored = true;
-                    } else {
+
+                    // 18-Jul-2023, tatu: [databind#3948] Need to retain if there was explicit
+                    //   ignoral marker
+                    } else if (!ignored) {
                         continue;
                     }
                 }

src/test/java/com/fasterxml/jackson/databind/introspect/Transient3948Test.java

@@ -8,6 +8,8 @@
 import com.fasterxml.jackson.databind.ObjectMapper;
 import java.io.Serializable;
 
+// With [databind#3948] we should not drop `@JsonIgnore` regardless
+// of "transient" keyword.
 public class Transient3948Test extends BaseMapTest {
 
     @JsonPropertyOrder(alphabetic = true)
@@ -43,9 +45,9 @@ public String getD() {
         }
     }
 
-    final ObjectMapper DEFAULT_MAPPER = newJsonMapper();
+    private final ObjectMapper DEFAULT_MAPPER = newJsonMapper();
 
-    final ObjectMapper MAPPER_TRANSIENT = jsonMapperBuilder()
+    private final ObjectMapper MAPPER_TRANSIENT = jsonMapperBuilder()
             .configure(MapperFeature.PROPAGATE_TRANSIENT_MARKER, true)
             .build();
 
@@ -54,7 +56,7 @@ public void testJsonIgnoreSerialization() throws Exception {
 
         String json = DEFAULT_MAPPER.writeValueAsString(obj1);
 
-        assertEquals(a2q("{'a':'hello','b':'world','cat':'jackson','dog':'databind'}"), json);
+        assertEquals(a2q("{'a':'hello','cat':'jackson','dog':'databind'}"), json);
     }
 
     public void testJsonIgnoreSerializationTransient() throws Exception {