From ebc8975efd78c7f832068d7e0ef892083c99ec35 Mon Sep 17 00:00:00 2001
From: Shay Banon <kimchy@gmail.com>
Date: Wed, 6 Nov 2013 01:10:58 +0100
Subject: [PATCH] NPE when closing XContentBuilder and using 'pretty' query
 parameter fixes #4100

---
 .../xcontent/json/JsonXContentGenerator.java  |  3 +++
 .../builder/XContentBuilderTests.java         | 20 ++++++++++++++++++-
 2 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/src/main/java/org/elasticsearch/common/xcontent/json/JsonXContentGenerator.java b/src/main/java/org/elasticsearch/common/xcontent/json/JsonXContentGenerator.java
index aa0bf321b3c..5e4fbfc5f5d 100644
--- a/src/main/java/org/elasticsearch/common/xcontent/json/JsonXContentGenerator.java
+++ b/src/main/java/org/elasticsearch/common/xcontent/json/JsonXContentGenerator.java
@@ -327,6 +327,9 @@ public class JsonXContentGenerator implements XContentGenerator {
 
     @Override
     public void close() throws IOException {
+        if (generator.isClosed()) {
+            return;
+        }
         if (writeLineFeedAtEnd) {
             flush();
             generator.writeRaw(LF);
diff --git a/src/test/java/org/elasticsearch/common/xcontent/builder/XContentBuilderTests.java b/src/test/java/org/elasticsearch/common/xcontent/builder/XContentBuilderTests.java
index b70028a13af..c8bd9b2a1f8 100644
--- a/src/test/java/org/elasticsearch/common/xcontent/builder/XContentBuilderTests.java
+++ b/src/test/java/org/elasticsearch/common/xcontent/builder/XContentBuilderTests.java
@@ -33,7 +33,6 @@ import java.util.*;
 
 import static org.elasticsearch.common.xcontent.XContentBuilder.FieldCaseConversion.CAMELCASE;
 import static org.elasticsearch.common.xcontent.XContentBuilder.FieldCaseConversion.UNDERSCORE;
-import static org.hamcrest.MatcherAssert.assertThat;
 import static org.hamcrest.Matchers.equalTo;
 
 /**
@@ -41,6 +40,25 @@ import static org.hamcrest.Matchers.equalTo;
  */
 public class XContentBuilderTests extends ElasticsearchTestCase {
 
+    @Test
+    public void testPrettyWithLfAtEnd() throws Exception {
+        FastCharArrayWriter writer = new FastCharArrayWriter();
+        XContentGenerator generator = XContentFactory.xContent(XContentType.JSON).createGenerator(writer);
+        generator.usePrettyPrint();
+        generator.usePrintLineFeedAtEnd();
+
+        generator.writeStartObject();
+        generator.writeStringField("test", "value");
+        generator.writeEndObject();
+        generator.flush();
+
+        generator.close();
+        // double close, and check there is no error...
+        generator.close();
+
+        assertThat(writer.unsafeCharArray()[writer.size() - 1], equalTo('\n'));
+    }
+
     @Test
     public void verifyReuseJsonGenerator() throws Exception {
         FastCharArrayWriter writer = new FastCharArrayWriter();