Solve NPE part of #296, add test

Author: cowtowncoder

datetime/src/main/java/com/fasterxml/jackson/datatype/jsr310/ser/LocalDateSerializer.java

@@ -83,14 +83,12 @@ public void serializeWithType(LocalDate value, JsonGenerator g,
         WritableTypeId typeIdDef = typeSer.writeTypePrefix(g,
                 typeSer.typeId(value, serializationShape(provider)));
         // need to write out to avoid double-writing array markers
-        switch (typeIdDef.valueShape) {
-        case START_ARRAY:
+        JsonToken shape = (typeIdDef == null) ? null : typeIdDef.valueShape;
+        if (shape == JsonToken.START_ARRAY) {
             _serializeAsArrayContents(value, g, provider);
-            break;
-        case VALUE_NUMBER_INT:
+        } else if (shape == JsonToken.VALUE_NUMBER_INT) {
             g.writeNumber(value.toEpochDay());
-            break;
-        default:
+        } else {
             g.writeString((_formatter == null) ? value.toString() : value.format(_formatter));
         }
         typeSer.writeTypeSuffix(g, typeIdDef);

datetime/src/main/java/com/fasterxml/jackson/datatype/jsr310/ser/LocalDateTimeSerializer.java

@@ -86,7 +86,7 @@ public void serializeWithType(LocalDateTime value, JsonGenerator g, SerializerPr
         WritableTypeId typeIdDef = typeSer.writeTypePrefix(g,
                 typeSer.typeId(value, serializationShape(provider)));
         // need to write out to avoid double-writing array markers
-        if (typeIdDef.valueShape == JsonToken.START_ARRAY) {
+        if ((typeIdDef != null) && typeIdDef.valueShape == JsonToken.START_ARRAY) {
             _serializeAsArrayContents(value, g, provider);
         } else {
             DateTimeFormatter dtf = _formatter;

datetime/src/main/java/com/fasterxml/jackson/datatype/jsr310/ser/LocalTimeSerializer.java

@@ -94,7 +94,8 @@ public void serializeWithType(LocalTime value, JsonGenerator g,
         WritableTypeId typeIdDef = typeSer.writeTypePrefix(g,
                 typeSer.typeId(value, serializationShape(provider)));
         // need to write out to avoid double-writing array markers
-        if (typeIdDef.valueShape == JsonToken.START_ARRAY) {
+        if ((typeIdDef != null)
+                && typeIdDef.valueShape == JsonToken.START_ARRAY) {
             _serializeAsArrayContents(value, g, provider);
         } else {
             DateTimeFormatter dtf = _formatter;

datetime/src/test/java/com/fasterxml/jackson/datatype/jsr310/misc/DeductionTypeSerialization296Test.java

@@ -0,0 +1,55 @@
+package com.fasterxml.jackson.datatype.jsr310.misc;
+
+import java.time.LocalDate;
+import java.time.LocalDateTime;
+import java.time.LocalTime;
+import java.time.Month;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+import com.fasterxml.jackson.annotation.JsonTypeInfo;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.SerializationFeature;
+import com.fasterxml.jackson.datatype.jsr310.ModuleTestBase;
+
+// for [modules-java8#296]: problem with `JsonTypeInfo.Id.DEDUCTION`
+public class DeductionTypeSerialization296Test extends ModuleTestBase
+{
+    static class Wrapper {
+        @JsonTypeInfo(use = JsonTypeInfo.Id.DEDUCTION)
+        public Object value;
+
+        public Wrapper(Object value) {
+            this.value = value;
+        }
+    }
+
+    private final ObjectMapper MAPPER = mapperBuilder()
+            .disable(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS)
+            .build();
+
+    @Test
+    public void testLocalDate() throws Exception
+    {
+        LocalDate date = LocalDate.of(1986, Month.JANUARY, 17);
+        Assert.assertEquals(a2q("{'value':'1986-01-17'}"),
+                MAPPER.writeValueAsString(new Wrapper(date)));
+    }
+
+    @Test
+    public void testLocalDateTime() throws Exception
+    {
+        LocalDateTime datetime = LocalDateTime.of(2013, Month.AUGUST, 21, 9, 22, 0, 57);
+        Assert.assertEquals(a2q("{'value':'2013-08-21T09:22:00.000000057'}"),
+                MAPPER.writeValueAsString(new Wrapper(datetime)));
+    }
+
+    @Test
+    public void testLocalTime() throws Exception
+    {
+        LocalTime time = LocalTime.of(9, 22, 57);
+        Assert.assertEquals(a2q("{'value':'09:22:57'}"),
+                MAPPER.writeValueAsString(new Wrapper(time)));
+    }
+}