Merge branch '2.11'

Author: cowtowncoder

release-notes/CREDITS-2.x

@@ -1013,6 +1013,11 @@ Stefan Wendt (stewe@github)
   * Reported #2560: Check `WRAP_EXCEPTIONS` in `CollectionDeserializer.handleNonArray()`
   (2.10.2)
 
+Greg Arakelian (arakelian@github)
+  * Reported #2566: `MissingNode.toString()` returns `null` (4 character token) instead
+    of empty string
+  (2.10.2)
+
 Máté Rédecsi (rmatesz@github)
   * Reported #953: i-I case convertion problem in Turkish locale with case-insensitive deserialization
  (2.11.0)

release-notes/VERSION-2.x

@@ -40,7 +40,9 @@ Project: jackson-databind
 #2560: Check `WRAP_EXCEPTIONS` in `CollectionDeserializer.handleNonArray()`
  (reported by Stefan W)
 #2564: Fix `IllegalArgumentException` on empty input collection for `ArrayBlockingQueue`
- (repoted, fix suggested by yamert89@github)
+ (reported, fix suggested by yamert89@github)
+#2566: `MissingNode.toString()` returns `null` (4 character token) instead of empty string
+ (reported by Greg A)
 #2567: Incorrect target type for arrays when providing nulls and nulls are disabled
  (reported by João G)
 

src/main/java/com/fasterxml/jackson/databind/node/BaseJsonNode.java

@@ -135,7 +135,7 @@ public abstract void serializeWithType(JsonGenerator jgen, SerializerProvider pr
 
     /*
    /**********************************************************
-   /* Std method overrides
+   /* Standard method overrides
    /**********************************************************
     */
 

src/main/java/com/fasterxml/jackson/databind/node/MissingNode.java

@@ -86,20 +86,6 @@ public void serializeWithType(JsonGenerator g, SerializerProvider provider,
     {
         g.writeNull();
     }
-    
-    @Override
-    public boolean equals(Object o)
-    {
-        /* Hmmh. Since there's just a singleton instance, this
-         * fails in all cases but with identity comparison.
-         * However: if this placeholder value was to be considered
-         * similar to SQL NULL, it shouldn't even equal itself?
-         * That might cause problems when dealing with collections
-         * like Sets... so for now, let's let identity comparison
-         * return true.
-         */
-        return (o == this);
-    }
 
     @SuppressWarnings("unchecked")
     @Override
@@ -113,11 +99,6 @@ public JsonNode requireNonNull() {
         return _reportRequiredViolation("requireNonNull() called on `MissingNode`");
     }
 
-    @Override
-    public int hashCode() {
-        return JsonNodeType.MISSING.ordinal();
-    }
-
     @Override
     public JsonNode get(int index) {
         return null;
@@ -158,4 +139,39 @@ public List<String> findValuesAsText(String fieldName, List<String> foundSoFar)
     public List<JsonNode> findParents(String fieldName, List<JsonNode> foundSoFar) {
         return foundSoFar;
     }
+
+    /*
+    /**********************************************************
+    /* Standard method overrides
+    /**********************************************************
+     */
+
+    @Override
+    public boolean equals(Object o)
+    {
+        // Hmmh. Since there's just a singleton instance, this fails in all cases
+        // but with identity comparison.
+        // However: if this placeholder value was to be considered similar to SQL NULL,
+        // it shouldn't even equal itself?
+        // That might cause problems when dealing with collections like Sets...
+        // so for now, let's let identity comparison return true.
+        return (o == this);
+    }
+
+    @Override
+    public int hashCode() {
+        return JsonNodeType.MISSING.ordinal();
+    }
+
+    // 10-Dec-2019, tatu: Bit tricky case, see [databind#2566], but seems
+    //    best NOT to produce legit JSON.
+    @Override
+    public String toString() {
+        return "";
+    }
+
+    @Override
+    public String toPrettyString() {
+        return "";
+    }
 }

src/test/java/com/fasterxml/jackson/databind/node/TestMissingNode.java

@@ -16,7 +16,9 @@ public void testMissing()
         assertEquals("", n.asText());
         assertStandardEquals(n);
         // 10-Dec-2018, tatu: With 2.10, should serialize same as via ObjectMapper/ObjectWriter
-        assertEquals("null", n.toString());
+        // 10-Dec-2019, tatu: Surprise! No, this is not how it worked in 2.9, nor does it make
+        //    sense... see [databind#2566] for details
+        assertEquals("", n.toString());
 
         assertNodeNumbersForNonNumeric(n);