Consume request body before flushing the buffer

This is continuation from https://git.eclipse.org/r/#/c/94249/. When an
error happens, we might not read the entire stream. Consume the request
body before we flush the buffer.

Change-Id: Ia473a04ace600653b2d1f2822e3023570d992410
Signed-off-by: Masaya Suzuki <masayasuzuki@google.com>

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

@@ -719,7 +719,7 @@ public class UploadPack {
 	}
 
 	private void service() throws IOException {
-		boolean sendPack;
+		boolean sendPack = false;
 		// If it's a non-bidi request, we need to read the entire request before
 		// writing a response. Buffer the response until then.
 		try {
@@ -752,6 +752,17 @@ public class UploadPack {
 			if (!clientShallowCommits.isEmpty())
 				walk.assumeShallow(clientShallowCommits);
 			sendPack = negotiate();
+			if (sendPack && !biDirectionalPipe) {
+				// Ensure the request was fully consumed. Any remaining input must
+				// be a protocol error. If we aren't at EOF the implementation is broken.
+				int eof = rawIn.read();
+				if (0 <= eof) {
+					sendPack = false;
+					throw new CorruptObjectException(MessageFormat.format(
+							JGitText.get().expectedEOFReceived,
+							"\\x" + Integer.toHexString(eof))); //$NON-NLS-1$
+				}
+			}
 		} catch (ServiceMayNotContinueException err) {
 			if (!err.isOutput() && err.getMessage() != null) {
 				try {
@@ -778,6 +789,11 @@ public class UploadPack {
 			}
 			throw err;
 		} finally {
+			if (!sendPack && !biDirectionalPipe) {
+				while (0 < rawIn.skip(2048) || 0 <= rawIn.read()) {
+					// Discard until EOF.
+				}
+			}
 			rawOut.stopBuffering();
 		}
 
@@ -1390,17 +1406,6 @@ public class UploadPack {
 	private void sendPack() throws IOException {
 		final boolean sideband = options.contains(OPTION_SIDE_BAND)
 				|| options.contains(OPTION_SIDE_BAND_64K);
-
-		if (!biDirectionalPipe) {
-			// Ensure the request was fully consumed. Any remaining input must
-			// be a protocol error. If we aren't at EOF the implementation is broken.
-			int eof = rawIn.read();
-			if (0 <= eof)
-				throw new CorruptObjectException(MessageFormat.format(
-						JGitText.get().expectedEOFReceived,
-						"\\x" + Integer.toHexString(eof))); //$NON-NLS-1$
-		}
-
 		if (sideband) {
 			try {
 				sendPack(true);