From 6278d88d2f46e5facebc805b1dc0cd015eaf35b9 Mon Sep 17 00:00:00 2001
From: Norman Maurer <nmaurer@redhat.com>
Date: Fri, 26 Jul 2013 11:46:26 +0200
Subject: [PATCH] [#1656] Fix IndexOutOfBoundsException in
 MessageToMessageException

---
 .../codec/MessageToMessageEncoder.java        |  8 ++--
 .../codec/MessageToMessageEncoderTest.java    | 40 +++++++++++++++++++
 2 files changed, 45 insertions(+), 3 deletions(-)
 create mode 100644 codec/src/test/java/io/netty/handler/codec/MessageToMessageEncoderTest.java

diff --git a/codec/src/main/java/io/netty/handler/codec/MessageToMessageEncoder.java b/codec/src/main/java/io/netty/handler/codec/MessageToMessageEncoder.java
index 401f35ed12..d0e98efa44 100644
--- a/codec/src/main/java/io/netty/handler/codec/MessageToMessageEncoder.java
+++ b/codec/src/main/java/io/netty/handler/codec/MessageToMessageEncoder.java
@@ -108,10 +108,12 @@ public abstract class MessageToMessageEncoder<I> extends ChannelOutboundHandlerA
         } finally {
             if (out != null) {
                 final int sizeMinusOne = out.size() - 1;
-                for (int i = 0; i < sizeMinusOne; i ++) {
-                    ctx.write(out.get(i));
+                if (sizeMinusOne >= 0) {
+                    for (int i = 0; i < sizeMinusOne; i ++) {
+                        ctx.write(out.get(i));
+                    }
+                    ctx.write(out.get(sizeMinusOne), promise);
                 }
-                ctx.write(out.get(sizeMinusOne), promise);
                 out.recycle();
             }
         }
diff --git a/codec/src/test/java/io/netty/handler/codec/MessageToMessageEncoderTest.java b/codec/src/test/java/io/netty/handler/codec/MessageToMessageEncoderTest.java
new file mode 100644
index 0000000000..322631adf6
--- /dev/null
+++ b/codec/src/test/java/io/netty/handler/codec/MessageToMessageEncoderTest.java
@@ -0,0 +1,40 @@
+/*
+ * Copyright 2013 The Netty Project
+ *
+ * The Netty Project licenses this file to you under the Apache License,
+ * version 2.0 (the "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at:
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ */
+package io.netty.handler.codec;
+
+import io.netty.channel.ChannelHandlerContext;
+import io.netty.channel.embedded.EmbeddedChannel;
+import org.junit.Test;
+
+import java.util.List;
+
+
+public class MessageToMessageEncoderTest {
+
+    /**
+     * Test-case for https://github.com/netty/netty/issues/1656
+     */
+    @Test(expected = EncoderException.class)
+    public void testException() {
+        EmbeddedChannel channel = new EmbeddedChannel(new MessageToMessageEncoder<Object>() {
+            @Override
+            protected void encode(ChannelHandlerContext ctx, Object msg, List<Object> out) throws Exception {
+                throw new Exception();
+            }
+        });
+        channel.writeOutbound(new Object());
+    }
+}