Fixed #5094: add lazy construction of BeanDescription for deserialization (#5096)

Author: cowtowncoder

release-notes/VERSION

@@ -9,6 +9,8 @@ Versions: 3.x (for earlier see VERSION-2.x)
 
 #5093: Change the way `BeanDescription` passed during serializer construction
  to use `Supplier`
+#5094: Change the way `BeanDescription` passed during deserializer construction
+ to use `Supplier`
 
 3.0.0-rc3 (13-Apr-2025)
 

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

@@ -39,14 +39,14 @@ public JavaType findTypeMapping(DeserializationConfig config, JavaType type) {
      * including defaulting.
      *
      * @param config Configuration in use
-     * @param typeDesc Description of the POJO type to resolve
+     * @param typeDescRef Description of the POJO type to resolve
      *
      * @return Resolved concrete type (which should retain generic
      *    type parameters of input type, if any), if resolution succeeds;
      *    null if resolver does not know how to resolve given type
      */
     public JavaType resolveAbstractType(DeserializationConfig config,
-            BeanDescription typeDesc) {
+            BeanDescription.Supplier typeDescRef) {
         return null;
     }
 }

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

@@ -323,6 +323,10 @@ public AnnotatedClass getClassInfo() {
             return get().getClassInfo();
         }
 
+        public Annotations getClassAnnotations() {
+            return get().getClassAnnotations();
+        }
+
         @Override
         public BeanDescription get() {
             if (_beanDesc == null) {

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

@@ -536,12 +536,31 @@ public BeanDescription introspectBeanDescriptionForCreation(JavaType type) {
         return classIntrospector().introspectForCreation(type);
     }
 
+    public BeanDescription.Supplier lazyIntrospectBeanDescriptionForCreation(JavaType type) {
+        return new BeanDescription.Supplier(type) {
+            @Override
+            public BeanDescription _construct(JavaType forType) {
+                return introspectBeanDescriptionForCreation(forType);
+            }
+        };
+    }
+
     public BeanDescription introspectBeanDescriptionForBuilder(JavaType builderType,
             BeanDescription valueTypeDesc) {
         return classIntrospector().introspectForDeserializationWithBuilder(builderType,
                 valueTypeDesc);
     }
 
+    public BeanDescription.Supplier lazyIntrospectBeanDescriptionForBuilder(final JavaType builderType,
+            final BeanDescription valueTypeDesc) {
+        return new BeanDescription.Supplier(builderType) {
+            @Override
+            public BeanDescription _construct(JavaType forType) {
+                return introspectBeanDescriptionForBuilder(forType, valueTypeDesc);
+            }
+        };
+    }
+
     /*
     /**********************************************************************
     /* Misc config access
@@ -1890,8 +1909,15 @@ public <T> T reportBadTypeDefinition(BeanDescription bean,
      * regarding specific property (of a type), unrelated to actual JSON content to map.
      * Default behavior is to construct and throw a {@link DatabindException}.
      */
+    public <T> T reportBadPropertyDefinition(BeanDescription.Supplier beanDescRef,
+            BeanPropertyDefinition prop, String msg, Object... msgArgs)
+        throws DatabindException
+    {
+        return reportBadPropertyDefinition(beanDescRef.get(), prop, msg, msgArgs);
+    }
+
     public <T> T reportBadPropertyDefinition(BeanDescription bean, BeanPropertyDefinition prop,
-            String msg, Object... msgArgs)
+        String msg, Object... msgArgs)
         throws DatabindException
     {
         msg = _format(msg, msgArgs);

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

@@ -52,10 +52,10 @@ public class AbstractDeserializer
      *    to bind)
      */
     public AbstractDeserializer(BeanDeserializerBuilder builder,
-            BeanDescription beanDesc, Map<String, SettableBeanProperty> backRefProps,
+            Map<String, SettableBeanProperty> backRefProps,
             Map<String, SettableBeanProperty> props)
     {
-        _baseType = beanDesc.getType();
+        _baseType = builder.getType();
         _objectIdReader = builder.getObjectIdReader();
         _backRefProperties = backRefProps;
         _properties = props;
@@ -66,9 +66,9 @@ public AbstractDeserializer(BeanDeserializerBuilder builder,
         _acceptDouble = (cls == Double.TYPE) || cls.isAssignableFrom(Double.class);
     }
 
-    protected AbstractDeserializer(BeanDescription beanDesc)
+    protected AbstractDeserializer(JavaType baseType)
     {
-        _baseType = beanDesc.getType();
+        _baseType = baseType;
         _objectIdReader = null;
         _backRefProperties = null;
         Class<?> cls = _baseType.getRawClass();
@@ -96,8 +96,8 @@ protected AbstractDeserializer(AbstractDeserializer base,
      * Factory method used when constructing instances for non-POJO types, like
      * {@link java.util.Map}s.
      */
-    public static AbstractDeserializer constructForNonPOJO(BeanDescription beanDesc) {
-        return new AbstractDeserializer(beanDesc);
+    public static AbstractDeserializer constructForNonPOJO(BeanDescription.Supplier beanDescRef) {
+        return new AbstractDeserializer(beanDescRef.getType());
     }
 
     @Override