From f918d04da4cbc4fcce7037742fe12896002e9dd1 Mon Sep 17 00:00:00 2001
From: Tatu Saloranta <tatu.saloranta@iki.fi>
Date: Tue, 11 Apr 2023 18:27:05 -0700
Subject: [PATCH] Minor clean up post #3853

---
 release-notes/CREDITS-2.x                             |  6 ++++++
 release-notes/VERSION-2.x                             |  3 +++
 .../com/fasterxml/jackson/databind/MapperFeature.java | 11 ++++++++---
 .../jsontype/impl/AsPropertyTypeDeserializer.java     |  5 ++---
 .../jsontype/impl/StdTypeResolverBuilder.java         |  5 +++--
 5 files changed, 22 insertions(+), 8 deletions(-)

diff --git a/release-notes/CREDITS-2.x b/release-notes/CREDITS-2.x
index e11bc40258..e99f26633d 100644
--- a/release-notes/CREDITS-2.x
+++ b/release-notes/CREDITS-2.x
@@ -1613,3 +1613,9 @@ Patrick Strawderman (kilink@github)
 Matt Nelson (mattnelson@github)
   * Requested #3814: Enhance `StdNodeBasedDeserializer` to support `readerForUpdating`
    (2.15.0)
+
+Steve Storey (stevestorey@github)
+  * Contributed #3853: Add `MapperFeature.REQUIRE_TYPE_ID_FOR_SUBTYPES` to enable/disable
+    strict subtype Type Id handling
+   (2.15.0)
+
diff --git a/release-notes/VERSION-2.x b/release-notes/VERSION-2.x
index 783bf2b557..27a5eef2c0 100644
--- a/release-notes/VERSION-2.x
+++ b/release-notes/VERSION-2.x
@@ -17,6 +17,9 @@ Not yet released
 #3836: `Optional<Boolean>` is not recognized as boolean field
  (reported by @thnaeff)
  (fix contributed by Joo-Hyuk K)
+#3853: Add `MapperFeature.REQUIRE_TYPE_ID_FOR_SUBTYPES` to enable/disable
+  strict subtype Type Id handling
+ (contributed by Steve S))
 
 2.15.0-rc2 (28-Mar-2023)
 
diff --git a/src/main/java/com/fasterxml/jackson/databind/MapperFeature.java b/src/main/java/com/fasterxml/jackson/databind/MapperFeature.java
index d419712e34..2ecf7ee450 100644
--- a/src/main/java/com/fasterxml/jackson/databind/MapperFeature.java
+++ b/src/main/java/com/fasterxml/jackson/databind/MapperFeature.java
@@ -329,9 +329,14 @@ public enum MapperFeature implements ConfigFeature
     INFER_BUILDER_TYPE_BINDINGS(true),
 
     /**
-     * Feature that determines what happens when deserializing to a registered sub-type, but no
-     * type information has been provided. If enabled, then an {@link InvalidTypeIdException}
-     * will be thrown, if disabled then the deserialization will proceed without the type information.
+     * Feature that determines what happens when deserializing to a registered sub-type
+     * (polymorphic deserialization), but no type information has been provided.
+     * If enabled, then an {@code InvalidTypeIdException} will be thrown;
+     * if disabled then the deserialization may proceed without the type information
+     * if sub-type is legit target (non-abstract).
+     *<p>
+     * Feature is enabled by default for backwards-compatibility (same behavior
+     * as in Jackson 2.14 and earlier).
      *
      * @since 2.15
      */
diff --git a/src/main/java/com/fasterxml/jackson/databind/jsontype/impl/AsPropertyTypeDeserializer.java b/src/main/java/com/fasterxml/jackson/databind/jsontype/impl/AsPropertyTypeDeserializer.java
index 894102b317..3e1ae93eeb 100644
--- a/src/main/java/com/fasterxml/jackson/databind/jsontype/impl/AsPropertyTypeDeserializer.java
+++ b/src/main/java/com/fasterxml/jackson/databind/jsontype/impl/AsPropertyTypeDeserializer.java
@@ -62,9 +62,8 @@ public AsPropertyTypeDeserializer(JavaType bt, TypeIdResolver idRes,
             String typePropertyName, boolean typeIdVisible, JavaType defaultImpl,
             As inclusion)
     {
-        super(bt, idRes, typePropertyName, typeIdVisible, defaultImpl);
-        _inclusion = inclusion;
-        _strictTypeIdHandling = false;
+        this(bt, idRes, typePropertyName, typeIdVisible, defaultImpl, inclusion,
+                true);
     }
 
     public AsPropertyTypeDeserializer(AsPropertyTypeDeserializer src, BeanProperty property) {
diff --git a/src/main/java/com/fasterxml/jackson/databind/jsontype/impl/StdTypeResolverBuilder.java b/src/main/java/com/fasterxml/jackson/databind/jsontype/impl/StdTypeResolverBuilder.java
index 6ef4d18874..a98b92c0ed 100644
--- a/src/main/java/com/fasterxml/jackson/databind/jsontype/impl/StdTypeResolverBuilder.java
+++ b/src/main/java/com/fasterxml/jackson/databind/jsontype/impl/StdTypeResolverBuilder.java
@@ -421,13 +421,14 @@ protected boolean _strictTypeIdHandling(DeserializationConfig config, JavaType b
         if (config.isEnabled(MapperFeature.REQUIRE_TYPE_ID_FOR_SUBTYPES)) {
             return true;
         }
-        // Otherwise we will be strict if there's a type resolver
+        // Otherwise we will be strict if there's a type resolver: presumably
+        // target type is a (likely abstract) base type and cannot be used as target
         return _hasTypeResolver(config, baseType);
     }
 
     /**
      * Checks whether the given class has annotations indicating some type resolver
-     * is applied, for example {@link com.fasterxml.jackson.annotation.JsonSubTypes}.
+     * is applied, for example {@link com.fasterxml.jackson.annotation.JsonTypeInfo}.
      * Only initializes {@link #_hasTypeResolver} once if its value is null.
      *
      * @param config the deserialization configuration to use