diff --git a/org.eclipse.jgit.http.test/tst/org/eclipse/jgit/http/test/AdvertiseErrorTest.java b/org.eclipse.jgit.http.test/tst/org/eclipse/jgit/http/test/AdvertiseErrorTest.java
new file mode 100644
index 0000000..47d7806
--- /dev/null
+++ b/org.eclipse.jgit.http.test/tst/org/eclipse/jgit/http/test/AdvertiseErrorTest.java
@@ -0,0 +1,151 @@
+/*
+ * Copyright (C) 2010, Google Inc.
+ * and other copyright owners as documented in the project's IP log.
+ *
+ * This program and the accompanying materials are made available
+ * under the terms of the Eclipse Distribution License v1.0 which
+ * accompanies this distribution, is reproduced below, and is
+ * available at http://www.eclipse.org/org/documents/edl-v10.php
+ *
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or
+ * without modification, are permitted provided that the following
+ * conditions are met:
+ *
+ * - Redistributions of source code must retain the above copyright
+ *   notice, this list of conditions and the following disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above
+ *   copyright notice, this list of conditions and the following
+ *   disclaimer in the documentation and/or other materials provided
+ *   with the distribution.
+ *
+ * - Neither the name of the Eclipse Foundation, Inc. nor the
+ *   names of its contributors may be used to endorse or promote
+ *   products derived from this software without specific prior
+ *   written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
+ * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
+ * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+package org.eclipse.jgit.http.test;
+
+import java.util.Collections;
+
+import javax.servlet.http.HttpServletRequest;
+
+import org.eclipse.jetty.servlet.ServletContextHandler;
+import org.eclipse.jetty.servlet.ServletHolder;
+import org.eclipse.jgit.errors.RemoteRepositoryException;
+import org.eclipse.jgit.errors.RepositoryNotFoundException;
+import org.eclipse.jgit.http.server.GitServlet;
+import org.eclipse.jgit.http.server.resolver.DefaultReceivePackFactory;
+import org.eclipse.jgit.http.server.resolver.RepositoryResolver;
+import org.eclipse.jgit.http.server.resolver.ServiceNotAuthorizedException;
+import org.eclipse.jgit.http.server.resolver.ServiceNotEnabledException;
+import org.eclipse.jgit.http.test.util.HttpTestCase;
+import org.eclipse.jgit.junit.TestRepository;
+import org.eclipse.jgit.lib.Constants;
+import org.eclipse.jgit.lib.NullProgressMonitor;
+import org.eclipse.jgit.lib.ObjectId;
+import org.eclipse.jgit.lib.Repository;
+import org.eclipse.jgit.lib.RepositoryConfig;
+import org.eclipse.jgit.revwalk.RevBlob;
+import org.eclipse.jgit.revwalk.RevCommit;
+import org.eclipse.jgit.transport.ReceivePack;
+import org.eclipse.jgit.transport.RemoteRefUpdate;
+import org.eclipse.jgit.transport.Transport;
+import org.eclipse.jgit.transport.URIish;
+
+public class AdvertiseErrorTest extends HttpTestCase {
+	private Repository remoteRepository;
+
+	private URIish remoteURI;
+
+	protected void setUp() throws Exception {
+		super.setUp();
+
+		final TestRepository src = createTestRepository();
+		final String srcName = src.getRepository().getDirectory().getName();
+
+		ServletContextHandler app = server.addContext("/git");
+		GitServlet gs = new GitServlet();
+		gs.setRepositoryResolver(new RepositoryResolver() {
+			public Repository open(HttpServletRequest req, String name)
+					throws RepositoryNotFoundException,
+					ServiceNotEnabledException {
+				if (!name.equals(srcName))
+					throw new RepositoryNotFoundException(name);
+
+				final Repository db = src.getRepository();
+				db.incrementOpen();
+				return db;
+			}
+		});
+		gs.setReceivePackFactory(new DefaultReceivePackFactory() {
+			public ReceivePack create(HttpServletRequest req, Repository db)
+					throws ServiceNotEnabledException,
+					ServiceNotAuthorizedException {
+				ReceivePack rp = super.create(req, db);
+				rp.sendError("message line 1");
+				rp.sendError("no soup for you!");
+				rp.sendError("come back next year!");
+				return rp;
+			}
+
+		});
+		app.addServlet(new ServletHolder(gs), "/*");
+
+		server.setUp();
+
+		remoteRepository = src.getRepository();
+		remoteURI = toURIish(app, srcName);
+
+		RepositoryConfig cfg = remoteRepository.getConfig();
+		cfg.setBoolean("http", null, "receivepack", true);
+		cfg.save();
+	}
+
+	public void testPush_CreateBranch() throws Exception {
+		final TestRepository src = createTestRepository();
+		final RevBlob Q_txt = src.blob("new text");
+		final RevCommit Q = src.commit().add("Q", Q_txt).create();
+		final Repository db = src.getRepository();
+		final String dstName = Constants.R_HEADS + "new.branch";
+		final Transport t = Transport.open(db, remoteURI);
+		try {
+			final String srcExpr = Q.name();
+			final boolean forceUpdate = false;
+			final String localName = null;
+			final ObjectId oldId = null;
+
+			RemoteRefUpdate update = new RemoteRefUpdate(src.getRepository(),
+					srcExpr, dstName, forceUpdate, localName, oldId);
+			try {
+				t.push(NullProgressMonitor.INSTANCE, Collections
+						.singleton(update));
+				fail("push completed without throwing exception");
+			} catch (RemoteRepositoryException error) {
+				assertEquals(remoteURI + ": message line 1\n" //
+						+ "no soup for you!\n" //
+						+ "come back next year!", //
+						error.getMessage());
+			}
+		} finally {
+			t.close();
+		}
+	}
+}
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/transport/ReceivePack.java b/org.eclipse.jgit/src/org/eclipse/jgit/transport/ReceivePack.java
index c5bbdac..d799658 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/transport/ReceivePack.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/transport/ReceivePack.java
@@ -163,6 +163,9 @@ public class ReceivePack {
 	/** Commands to execute, as received by the client. */
 	private List<ReceiveCommand> commands;
 
+	/** Error to display instead of advertising the references. */
+	private StringBuilder advertiseError;
+
 	/** An exception caught while unpacking and fsck'ing the objects. */
 	private Throwable unpackError;
 
@@ -428,10 +431,17 @@ public List<ReceiveCommand> getAllCommands() {
 	}
 
 	/**
-	 * Send an error message to the client, if it supports receiving them.
+	 * Send an error message to the client.
 	 * <p>
-	 * If the client doesn't support receiving messages, the message will be
-	 * discarded, with no other indication to the caller or to the client.
+	 * If any error messages are sent before the references are advertised to
+	 * the client, the errors will be sent instead of the advertisement and the
+	 * receive operation will be aborted. All clients should receive and display
+	 * such early stage errors.
+	 * <p>
+	 * If the reference advertisements have already been sent, messages are sent
+	 * in a side channel. If the client doesn't support receiving messages, the
+	 * message will be discarded, with no other indication to the caller or to
+	 * the client.
 	 * <p>
 	 * {@link PreReceiveHook}s should always try to use
 	 * {@link ReceiveCommand#setResult(Result, String)} with a result status of
@@ -444,11 +454,17 @@ public List<ReceiveCommand> getAllCommands() {
 	 *            string must not end with an LF, and must not contain an LF.
 	 */
 	public void sendError(final String what) {
-		try {
-			if (msgs != null)
-				msgs.write("error: " + what + "\n");
-		} catch (IOException e) {
-			// Ignore write failures.
+		if (refs == null) {
+			if (advertiseError == null)
+				advertiseError = new StringBuilder();
+			advertiseError.append(what).append('\n');
+		} else {
+			try {
+				if (msgs != null)
+					msgs.write("error: " + what + "\n");
+			} catch (IOException e) {
+				// Ignore write failures.
+			}
 		}
 	}
 
@@ -558,6 +574,8 @@ private void service() throws IOException {
 			sendAdvertisedRefs(new PacketLineOutRefAdvertiser(pckOut));
 		else
 			refs = refFilter.filter(db.getAllRefs());
+		if (advertiseError != null)
+			return;
 		recvCommands();
 		if (!commands.isEmpty()) {
 			enableCapabilities();
@@ -618,6 +636,11 @@ private void unlockPack() {
 	 *             the formatter failed to write an advertisement.
 	 */
 	public void sendAdvertisedRefs(final RefAdvertiser adv) throws IOException {
+		if (advertiseError != null) {
+			adv.writeOne("ERR " + advertiseError);
+			return;
+		}
+
 		final RevFlag advertised = walk.newFlag("ADVERTISED");
 		adv.init(walk, advertised);
 		adv.advertiseCapability(CAPABILITY_SIDE_BAND_64K);