Fix #2309 (NPE for Enum.toString()) as suggested by Ben A

Author: cowtowncoder

release-notes/CREDITS-2.x

@@ -892,6 +892,10 @@ Pavel Chervakov (pacher@github)
   * Reported #2230: `WRITE_BIGDECIMAL_AS_PLAIN` is ignored if `@JsonFormat` is used
    (2.10.0)
 
+Ben Anderson (andersonbd1@github)
+  * Reported, suggested fix for #2309: READ_ENUMS_USING_TO_STRING doesn't support null values
+   (2.10.0)
+
 Manuel Hegner (manuel-hegner@github)
   * Suggested #2311: Unnecessary MultiView creation for property writers
    (2.10.0)

release-notes/VERSION-2.x

@@ -4,6 +4,16 @@ Project: jackson-databind
 === Releases === 
 ------------------------------------------------------------------------
 
+2.10.0-final (not yet released)
+
+#2309: READ_ENUMS_USING_TO_STRING doesn't support null values
+ (reported, fix suggested by Ben A)
+#2442: `ArrayNode.addAll()` adds raw `null` values which cause NPE on `deepCopy()`
+  and `toString()`
+ (reported, fix contributed by Hesham M)
+#2446: Java 11: Unable to load JDK7 types (annotations, java.nio.file.Path): no Java7 support added
+ (reported by David C)
+
 2.10.0.pr2 (31-Aug-2019)
 
 #2237: Add "required" methods in `JsonNode`: `required(String | int)`,
@@ -34,11 +44,6 @@ Project: jackson-databind
 #2430: Change `ObjectMapper.valueToTree()` to convert `null` to `NullNode`
 #2433: Improve `NullNode.equals()`
  (suggested by David B)
-#2442: `ArrayNode.addAll()` adds raw `null` values which cause NPE on `deepCopy()`
-  and `toString()`
- (reported, fix contributed by Hesham M)
-#2446: Java 11: Unable to load JDK7 types (annotations, java.nio.file.Path): no Java7 support added
- (reported by David C)
 
 2.10.0.pr1 (19-Jul-2019)
 

src/main/java/com/fasterxml/jackson/databind/util/CompactStringObjectMap.java

@@ -53,6 +53,11 @@ public static <T> CompactStringObjectMap construct(Map<String,T> all)
         for (Map.Entry<String,T> entry : all.entrySet()) {
             String key = entry.getKey();
 
+            // 09-Sep-2019, tatu: [databind#2309] skip `null`s if any included
+            if (key == null) {
+                continue;
+            }
+            
             int slot = key.hashCode() & mask;
             int ix = slot+slot;
 

src/test/java/com/fasterxml/jackson/databind/deser/jdk/EnumDeserializationTest.java

@@ -7,12 +7,14 @@
 import com.fasterxml.jackson.annotation.*;
 import com.fasterxml.jackson.core.*;
 import com.fasterxml.jackson.core.type.TypeReference;
+
 import com.fasterxml.jackson.databind.*;
 import com.fasterxml.jackson.databind.annotation.JsonDeserialize;
 import com.fasterxml.jackson.databind.deser.std.FromStringDeserializer;
 import com.fasterxml.jackson.databind.deser.std.StdDeserializer;
 import com.fasterxml.jackson.databind.exc.InvalidFormatException;
 import com.fasterxml.jackson.databind.exc.MismatchedInputException;
+import com.fasterxml.jackson.databind.json.JsonMapper;
 import com.fasterxml.jackson.databind.module.SimpleModule;
 
 @SuppressWarnings("serial")
@@ -183,6 +185,25 @@ public static ObjectMapper setupObjectMapper(ObjectMapper mapper) {
         }
     }
 
+    // for [databind#2309]
+    static enum Enum2309 {
+        NON_NULL("NON_NULL"),
+        NULL(null),
+        OTHER("OTHER")
+        ;
+
+        private String value;
+
+        private Enum2309(String value) {
+            this.value = value;
+        }
+
+        @Override
+        public String toString() {
+            return value;
+        }
+    }        
+
     /*
     /**********************************************************
     /* Test methods
@@ -290,11 +311,11 @@ public void testNumbersToEnums() throws Exception
 
     public void testEnumsWithIndex() throws Exception
     {
-        ObjectMapper m = new ObjectMapper();
-        m.enable(SerializationFeature.WRITE_ENUMS_USING_INDEX);
-        String json = m.writeValueAsString(TestEnum.RULES);
+        String json = MAPPER.writer()
+                .with(SerializationFeature.WRITE_ENUMS_USING_INDEX)
+                .writeValueAsString(TestEnum.RULES);
         assertEquals(String.valueOf(TestEnum.RULES.ordinal()), json);
-        TestEnum result = m.readValue(json, TestEnum.class);
+        TestEnum result = MAPPER.readValue(json, TestEnum.class);
         assertSame(TestEnum.RULES, result);
     }
 
@@ -391,10 +412,10 @@ public void testGenericEnumDeserialization() throws Exception
 
     // [databind#381]
     public void testUnwrappedEnum() throws Exception {
-        final ObjectMapper mapper = newJsonMapper();
-        mapper.enable(DeserializationFeature.UNWRAP_SINGLE_VALUE_ARRAYS);
-        
-        assertEquals(TestEnum.JACKSON, mapper.readValue("[" + quote("JACKSON") + "]", TestEnum.class));
+        assertEquals(TestEnum.JACKSON,
+                MAPPER.readerFor(TestEnum.class)
+                    .with(DeserializationFeature.UNWRAP_SINGLE_VALUE_ARRAYS)
+                    .readValue("[" + quote("JACKSON") + "]"));
     }
 
     public void testUnwrappedEnumException() throws Exception {
@@ -422,11 +443,12 @@ public void testIndexAsString() throws Exception
         assertSame(TestEnum.values()[1], en);
 
         // [databind#1690]: unless prevented
-        final ObjectMapper mapper = jsonMapperBuilder()
-                .disable(MapperFeature.ALLOW_COERCION_OF_SCALARS)
-                .build();
         try {
-            en = mapper.readValue(quote("1"), TestEnum.class);
+            en = JsonMapper.builder()
+                    .configure(MapperFeature.ALLOW_COERCION_OF_SCALARS, false)
+                    .build()
+                    .readerFor(TestEnum.class)
+                    .readValue(quote("1"));
             fail("Should not pass");
         } catch (MismatchedInputException e) {
             verifyException(e, "Cannot deserialize value of type");
@@ -528,4 +550,13 @@ public void testExceptionFromCustomEnumKeyDeserializer() throws Exception {
             assertTrue(e.getMessage().contains("Undefined AnEnum"));
         }
     }
+
+    // [databind#2309]
+    public void testEnumToStringNull2309() throws Exception
+    {
+        Enum2309 value = MAPPER.readerFor(Enum2309.class)
+                .with(DeserializationFeature.READ_ENUMS_USING_TO_STRING)
+                .readValue(quote("NON_NULL"));
+        assertEquals(Enum2309.NON_NULL, value);
+    }
 }