Fix #4777: make 0-args factory method become "default Creator" as in …

…2.17 (#4799)

release-notes/CREDITS-2.x

@@ -1849,6 +1849,10 @@ wrongwrong (@k163377)
    serializer lookup was done on the pre-converted value when _delegateSerializer was null
   (2.18.1)
 
+Bernd Ahlers (@bernd)
+ * Reported #4742: Deserialization with Builder, External type id, `@JsonCreator` failing
+  (2.18.2)
+
 Mike Minicki (@martel)
  * Reported #4788: `EnumFeature.WRITE_ENUMS_TO_LOWERCASE` overrides `@JsonProperty` values
   (2.18.2)

release-notes/VERSION-2.x

@@ -38,6 +38,11 @@ Project: jackson-databind
 
 #4733: Wrong serialization of Type Ids for certain types of Enum values
  (reported by @nlisker)
+#4742: Deserialization with Builder, External type id, `@JsonCreator` failing
+ (reported by Bernd A)
+#4777: `StdValueInstantiator.withArgsCreator` is now set for creators with
+  no arguments
+ (reported by @wrongwrong)
 #4783 Possibly wrong behavior of @JsonMerge
  (reported by @nlisker)
  (fix by Joo-Hyuk K)
@@ -70,7 +75,7 @@ Project: jackson-databind
  (fix by Joo-Hyuk K)
 #4749: Fixed a problem with `StdDelegatingSerializer#serializeWithType` looking up the serializer
   with the wrong argument
- (fix by wrongwrong)
+ (fix by @wrongwrong)
 
 2.18.0 (26-Sep-2024)
 

src/main/java/tools/jackson/databind/deser/BasicDeserializerFactory.java

@@ -217,10 +217,16 @@ protected ValueInstantiator _constructDefaultValueInstantiator(DeserializationCo
         if (potentialCreators.hasPropertiesBased()) {
             PotentialCreator primaryPropsBased = potentialCreators.propertiesBased;
 
-            // Start by assigning the primary (and only) properties-based creator
-            _addSelectedPropertiesBasedCreator(ctxt, beanDesc, creators,
-                    CreatorCandidate.construct(config,
-                            primaryPropsBased.creator(), primaryPropsBased.propertyDefs()));
+            // 12-Nov-2024, tatu: [databind#4777] We may have collected a 0-args Factory
+            //   method; and if so, may need to "pull it out" as default creator
+            if (primaryPropsBased.paramCount() == 0) {
+                creators.setDefaultCreator(primaryPropsBased.creator());
+            } else {
+                // Start by assigning the primary (and only) properties-based creator
+                _addSelectedPropertiesBasedCreator(ctxt, beanDesc, creators,
+                        CreatorCandidate.construct(config,
+                                primaryPropsBased.creator(), primaryPropsBased.propertyDefs()));
+            }
         }
 
         // Continue with explicitly annotated delegating Creators
@@ -240,9 +246,10 @@ protected ValueInstantiator _constructDefaultValueInstantiator(DeserializationCo
                 // First things first: the "default constructor" (zero-arg
                 // constructor; whether implicit or explicit) is NOT included
                 // in list of constructors, so needs to be handled separately.
-                AnnotatedConstructor defaultCtor = beanDesc.findDefaultConstructor();
-                if (defaultCtor != null) {
-                    if (!creators.hasDefaultCreator() || _hasCreatorAnnotation(config, defaultCtor)) {
+                // However, we may have added one for 0-args Factory method earlier, so:
+                if (!creators.hasDefaultCreator()) {
+                    AnnotatedConstructor defaultCtor = beanDesc.findDefaultConstructor();
+                    if (defaultCtor != null) {
                         creators.setDefaultCreator(defaultCtor);
                     }
                 }

src/test/java/tools/jackson/databind/tofix/JsonCreatorNoArgs4777Test.java → src/test/java/tools/jackson/databind/deser/creators/JsonCreatorNoArgs4777Test.java

@@ -1,38 +1,38 @@
-package tools.jackson.databind.tofix;
+package tools.jackson.databind.deser.creators;
 
 import org.junit.jupiter.api.Test;
 
 import com.fasterxml.jackson.annotation.JsonCreator;
+
 import tools.jackson.databind.*;
 import tools.jackson.databind.deser.*;
 import tools.jackson.databind.introspect.AnnotatedMethod;
 import tools.jackson.databind.introspect.AnnotatedWithParams;
 import tools.jackson.databind.json.JsonMapper;
 import tools.jackson.databind.module.SimpleModule;
 import tools.jackson.databind.testutil.DatabindTestUtil;
-import tools.jackson.databind.testutil.failure.JacksonTestFailureExpected;
 
 import static org.junit.jupiter.api.Assertions.assertNotNull;
 
 public class JsonCreatorNoArgs4777Test extends DatabindTestUtil
 {
-    static class Foo {
-        private Foo() { } 
+    static class Foo4777 {
+        Foo4777() { }
 
         @JsonCreator
-        static Foo create() {
-            return new Foo();
+        static Foo4777 create() {
+            return new Foo4777();
         }
     }
 
-    static class Instantiators implements ValueInstantiators {
+    static class Instantiators4777 implements ValueInstantiators {
         @Override
         public ValueInstantiator modifyValueInstantiator(
                 DeserializationConfig config,
                 BeanDescription beanDesc,
                 ValueInstantiator defaultInstantiator
         ) {
-            if (beanDesc.getBeanClass() == Foo.class) {
+            if (beanDesc.getBeanClass() == Foo4777.class) {
                 AnnotatedWithParams dc = defaultInstantiator.getDefaultCreator();
                 if (!(dc instanceof AnnotatedMethod)
                         || !dc.getName().equals("create")) {
@@ -52,18 +52,17 @@ public ValueInstantiator findValueInstantiator(DeserializationConfig config, Bea
     // For [databind#4777]
     @SuppressWarnings("serial")
     @Test
-    @JacksonTestFailureExpected
     public void testCreatorDetection4777() throws Exception {
         SimpleModule sm = new SimpleModule() {
             @Override
             public void setupModule(SetupContext context) {
                 super.setupModule(context);
-                context.addValueInstantiators(new Instantiators());
+                context.addValueInstantiators(new Instantiators4777());
             }
         };
         ObjectMapper mapper = JsonMapper.builder().addModule(sm).build();
 
-        Foo result = mapper.readValue("{}", Foo.class);
+        Foo4777 result = mapper.readValue("{}", Foo4777.class);
         assertNotNull(result);
     }
 }

src/test/java/tools/jackson/databind/tofix/JacksonBuilderCreatorSubtype4742Test.java → src/test/java/tools/jackson/databind/tofix/BuilderCreatorSubtype4742Test.java

@@ -14,9 +14,11 @@
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertInstanceOf;
 
+// For some reason, fixed in 2.18.2, but failing for 3.0 -- possibly
+// depends on another fix.
 // [databind#4742] Deserialization with Builder, External type id,
-//                @JsonCreator not yet implemented
-public class JacksonBuilderCreatorSubtype4742Test
+// @JsonCreator failing
+public class BuilderCreatorSubtype4742Test
     extends DatabindTestUtil
 {
     public static class Animals {
@@ -110,7 +112,7 @@ public String toString() {
 
     @JacksonTestFailureExpected
     @Test
-    public void testDeser() throws Exception
+    public void testDeser4742() throws Exception
     {
         final Animals animals = MAPPER.readValue(
                 "{\n" +
@@ -123,6 +125,5 @@ public void testDeser() throws Exception
         assertEquals(2, animals.animals.size());
         assertInstanceOf(BirdProperties.class, animals.animals.get(0).properties);
         assertInstanceOf(MammalProperties.class, animals.animals.get(1).properties);
-
     }
 }