Disallow unknown args to "fetch" in protocol v2

JGit's implementation of the fetch command of protocol v2, unlike its
implementation of ls-refs, currently tolerates unknown arguments.
Tighten fetch to not allow unrecognized arguments and add tests to
verify this behavior for both ls-refs and fetch.

Change-Id: I321161d568bd638252fab1a47b06b924d472a669
Signed-off-by: Jonathan Tan <jonathantanmy@google.com>

org.eclipse.jgit.test/tst/org/eclipse/jgit/transport/UploadPackTest.java

@@ -15,6 +15,7 @@ import java.io.ByteArrayInputStream;
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.StringWriter;
+import org.eclipse.jgit.errors.PackProtocolException;
 import org.eclipse.jgit.errors.TransportException;
 import org.eclipse.jgit.internal.storage.dfs.DfsGarbageCollector;
 import org.eclipse.jgit.internal.storage.dfs.DfsRepositoryDescription;
@@ -514,6 +515,17 @@ public class UploadPackTest {
 		assertTrue(pckIn.readString() == PacketLineIn.END);
 	}
 
+	@Test
+	public void testV2LsRefsUnrecognizedArgument() throws Exception {
+		thrown.expect(PackProtocolException.class);
+		thrown.expectMessage("unexpected invalid-argument");
+		uploadPackV2(
+			"command=ls-refs\n",
+			PacketLineIn.DELIM,
+			"invalid-argument\n",
+			PacketLineIn.END);
+	}
+
 	/*
 	 * Parse multiplexed packfile output from upload-pack using protocol V2
 	 * into the client repository.
@@ -973,6 +985,17 @@ public class UploadPackTest {
 		assertThat(pckIn.readString(), theInstance(PacketLineIn.END));
 	}
 
+	@Test
+	public void testV2FetchUnrecognizedArgument() throws Exception {
+		thrown.expect(PackProtocolException.class);
+		thrown.expectMessage("unexpected invalid-argument");
+		uploadPackV2(
+			"command=fetch\n",
+			PacketLineIn.DELIM,
+			"invalid-argument\n",
+			PacketLineIn.END);
+	}
+
 	private static class RejectAllRefFilter implements RefFilter {
 		@Override
 		public Map<String, Ref> filter(Map<String, Ref> refs) {

org.eclipse.jgit/src/org/eclipse/jgit/transport/UploadPack.java

@@ -1022,8 +1022,10 @@ public class UploadPack {
 					throw new PackProtocolException(
 							JGitText.get().deepenSinceWithDeepen);
 				}
+			} else {
+				throw new PackProtocolException(MessageFormat
+						.format(JGitText.get().unexpectedPacketLine, line));
 			}
-			// else ignore it
 		}
 		rawOut.stopBuffering();