From 525696d2af6066422129fa0d1dcd69e71f75db8c Mon Sep 17 00:00:00 2001
From: nick <nick@ntcoding.co.uk>
Date: Thu, 29 Oct 2015 08:16:24 +0000
Subject: [PATCH] example of fail on null creators for discussion

---
 .../jackson/databind/DeserializationFeature.java | 16 ++++++++++++++++
 .../databind/deser/impl/PropertyValueBuffer.java | 10 +++++++++-
 2 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/src/main/java/com/fasterxml/jackson/databind/DeserializationFeature.java b/src/main/java/com/fasterxml/jackson/databind/DeserializationFeature.java
index 53da367364..bb5bc685c9 100644
--- a/src/main/java/com/fasterxml/jackson/databind/DeserializationFeature.java
+++ b/src/main/java/com/fasterxml/jackson/databind/DeserializationFeature.java
@@ -230,6 +230,22 @@ public enum DeserializationFeature implements ConfigFeature
      * @since 2.6
      */
     FAIL_ON_MISSING_CREATOR_PROPERTIES(false),
+
+    /**
+     * Feature that determines what happens if one or more Creator properties (properties
+     * bound to parameters of Creator method (constructor or static factory method))
+     * are are bound to null values - either from the JSON or as a default value. This
+     * is useful if you want to avoid nulls in your codebase, and particularly useful
+     * if you are using Java or Scala optionals for non-mandatory fields.
+     *<p>
+     * Note that having an injectable value counts as "not missing".
+     *<p>
+     * Feature is disabled by default, so that no exception is thrown for missing creator
+     * property values, unless they are explicitly marked as `required`.
+     *
+     * @since 2.6
+     */
+    FAIL_ON_NULL_CREATOR_PROPERTIES(false),
     
     /**
      * Feature that determines whether Jackson code should catch
diff --git a/src/main/java/com/fasterxml/jackson/databind/deser/impl/PropertyValueBuffer.java b/src/main/java/com/fasterxml/jackson/databind/deser/impl/PropertyValueBuffer.java
index 32e100b7e0..7f63ee221e 100644
--- a/src/main/java/com/fasterxml/jackson/databind/deser/impl/PropertyValueBuffer.java
+++ b/src/main/java/com/fasterxml/jackson/databind/deser/impl/PropertyValueBuffer.java
@@ -145,9 +145,17 @@ protected Object _findMissing(SettableBeanProperty prop) throws JsonMappingExcep
             throw _context.mappingException("Missing creator property '%s' (index %d); DeserializationFeature.FAIL_ON_MISSING_CREATOR_PROPERTIES enabled",
                     prop.getName(), prop.getCreatorIndex());
         }
+
         // Third: default value
         JsonDeserializer<Object> deser = prop.getValueDeserializer();
-        return deser.getNullValue(_context);
+        Object value = deser.getNullValue(_context);
+
+        if (_context.isEnabled(DeserializationFeature.FAIL_ON_NULL_CREATOR_PROPERTIES) && value == null) {
+            throw _context.mappingException("Null value for creator property '%s'; DeserializationFeature.FAIL_ON_NULL_FOR_CREATOR_PARAMETERS enabled",
+                    prop.getName(), prop.getCreatorIndex());
+        }
+
+        return value;
     }
 
     /*