Fix missing trailing data on HTTP client upgrade

Motivation:

When HttpClientUpgradeHandler upgrades from HTTP/1 to another protocol,
it performs a two-step opertion:

1. Remove the SourceCodec (HttpClientCodec)
2. Add the UpgradeCodec

When HttpClientCodec is removed from the pipeline, the decoder being
removed triggers channelRead() event with the data left in its
cumulation buffer. However, this is not received by the UpgradeCodec
becuase it's not added yet. e.g. HTTP/2 SETTINGS frame sent by the
server can be missed out.

To fix the problem, we need to reverse the steps:

1. Add the UpgradeCodec
2. Remove the SourceCodec

However, this does not work as expected either, because UpgradeCodec can
send a greeting message such as HTTP/2 Preface. Such a greeting message
will be handled by the SourceCodec and will trigger an 'unsupported
message type' exception.

To fix the problem really, we need to make the upgrade process 3-step:

1. Remove/disable the encoder of SourceCodec
2. Add the UpgradeCodec
3. Remove the SourceCodec

Modifications:

- Add SourceCodec.prepareUpgradeFrom() so that SourceCodec can remove or
  disable its encoder
- Implement HttpClientCodec.prepareUpgradeFrom() properly
- Miscellaneous:
  - Log the related channel as well When logging the failure to send a
    GOAWAY

Result:

Cleartext HTTP/1-to-HTTP/2 upgrade works again.

codec-http/src/main/java/io/netty/handler/codec/http/HttpClientCodec.java

@@ -21,6 +21,7 @@ import io.netty.channel.ChannelHandlerContext;
 import io.netty.channel.ChannelPipeline;
 import io.netty.channel.CombinedChannelDuplexHandler;
 import io.netty.handler.codec.PrematureChannelClosureException;
+import io.netty.util.ReferenceCountUtil;
 
 import java.util.ArrayDeque;
 import java.util.List;
@@ -87,6 +88,14 @@ public final class HttpClientCodec extends CombinedChannelDuplexHandler<HttpResp
         this.failOnMissingResponse = failOnMissingResponse;
     }
 
+    /**
+     * Prepares to upgrade to another protocol from HTTP. Disables the {@link Encoder}.
+     */
+    @Override
+    public void prepareUpgradeFrom(ChannelHandlerContext ctx) {
+        ((Encoder) outboundHandler()).upgraded = true;
+    }
+
     /**
      * Upgrades to another protocol from HTTP. Removes the {@link Decoder} and {@link Encoder} from
      * the pipeline.
@@ -107,9 +116,17 @@ public final class HttpClientCodec extends CombinedChannelDuplexHandler<HttpResp
 
     private final class Encoder extends HttpRequestEncoder {
 
+        boolean upgraded;
+
         @Override
         protected void encode(
                 ChannelHandlerContext ctx, Object msg, List<Object> out) throws Exception {
+
+            if (upgraded) {
+                out.add(ReferenceCountUtil.retain(msg));
+                return;
+            }
+
             if (msg instanceof HttpRequest && !done) {
                 queue.offer(((HttpRequest) msg).method());
             }

codec-http/src/main/java/io/netty/handler/codec/http/HttpClientUpgradeHandler.java

@@ -62,6 +62,13 @@ public class HttpClientUpgradeHandler extends HttpObjectAggregator implements Ch
      * The source codec that is used in the pipeline initially.
      */
     public interface SourceCodec {
+
+        /**
+         * Removes or disables the encoder of this codec so that the {@link UpgradeCodec} can send an initial greeting
+         * (if any).
+         */
+        void prepareUpgradeFrom(ChannelHandlerContext ctx);
+
         /**
          * Removes this codec (i.e. all associated handlers) from the pipeline.
          */
@@ -222,8 +229,9 @@ public class HttpClientUpgradeHandler extends HttpObjectAggregator implements Ch
             }
 
             // Upgrade to the new protocol.
-            sourceCodec.upgradeFrom(ctx);
+            sourceCodec.prepareUpgradeFrom(ctx);
             upgradeCodec.upgradeTo(ctx, response);
+            sourceCodec.upgradeFrom(ctx);
 
             // Notify that the upgrade to the new protocol completed successfully.
             ctx.fireUserEventTriggered(UpgradeEvent.UPGRADE_SUCCESSFUL);

codec-http2/src/main/java/io/netty/handler/codec/http2/Http2ConnectionHandler.java

@@ -47,7 +47,6 @@ import static io.netty.handler.codec.http2.Http2Stream.State.IDLE;
 import static io.netty.util.CharsetUtil.UTF_8;
 import static io.netty.util.internal.ObjectUtil.checkNotNull;
 import static java.lang.Math.min;
-import static java.lang.String.format;
 import static java.util.concurrent.TimeUnit.MILLISECONDS;
 
 /**
@@ -724,20 +723,17 @@ public class Http2ConnectionHandler extends ByteToMessageDecoder implements Http
             if (future.isSuccess()) {
                 if (errorCode != NO_ERROR.code()) {
                     if (logger.isDebugEnabled()) {
-                        logger.debug(
-                                format("Sent GOAWAY: lastStreamId '%d', errorCode '%d', " +
-                                        "debugData '%s'. Forcing shutdown of the connection.",
-                                        lastStreamId, errorCode, debugData.toString(UTF_8)),
-                                        future.cause());
+                        logger.debug("{} Sent GOAWAY: lastStreamId '{}', errorCode '{}', " +
+                                     "debugData '{}'. Forcing shutdown of the connection.",
+                                     ctx.channel(), lastStreamId, errorCode, debugData.toString(UTF_8), future.cause());
                     }
                     ctx.close();
                 }
             } else {
                 if (logger.isErrorEnabled()) {
-                    logger.error(
-                            format("Sending GOAWAY failed: lastStreamId '%d', errorCode '%d', " +
-                                    "debugData '%s'. Forcing shutdown of the connection.",
-                                    lastStreamId, errorCode, debugData.toString(UTF_8)), future.cause());
+                    logger.error("{} Sending GOAWAY failed: lastStreamId '{}', errorCode '{}', " +
+                                 "debugData '{}'. Forcing shutdown of the connection.",
+                                 ctx.channel(), lastStreamId, errorCode, debugData.toString(UTF_8), future.cause());
                 }
                 ctx.close();
             }