[PATCH 1/3] receive-pack: redirect unpack-objects stdout to /dev/null

[Jeff King <peff@peff.net>]

The unpack-objects command should not generally produce any
output on stdout. However, if it's given extra input after
the packfile, it will spew the remainder to stdout. When
called by receive-pack, this means we will break protocol,
since our stdout is connected to the remote send-pack.

Signed-off-by: Jeff King <peff@peff.net>
---
I've never actually seen this bug in practice, but I noticed it while
auditing the outputs of receive-pack's children recently.

 builtin/receive-pack.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/builtin/receive-pack.c b/builtin/receive-pack.c
index 9145f1a..5ba0c98 100644
--- a/builtin/receive-pack.c
+++ b/builtin/receive-pack.c
@@ -815,6 +815,7 @@ static const char *unpack(void)
 
 	if (ntohl(hdr.hdr_entries) < unpack_limit) {
 		int code, i = 0;
+		struct child_process child;
 		const char *unpacker[5];
 		unpacker[i++] = "unpack-objects";
 		if (quiet)
@@ -823,7 +824,11 @@ static const char *unpack(void)
 			unpacker[i++] = "--strict";
 		unpacker[i++] = hdr_arg;
 		unpacker[i++] = NULL;
-		code = run_command_v_opt(unpacker, RUN_GIT_CMD);
+		memset(&child, 0, sizeof(child));
+		child.argv = unpacker;
+		child.no_stdout = 1;
+		child.git_cmd = 1;
+		code = run_command(&child);
 		if (!code)
 			return NULL;
 		return "unpack-objects abnormal exit";
-- 
1.7.11.7.15.g085c6bd