index-helper: add --detach

We detach after creating and opening the socket, because otherwise
we might return control to the shell before index-helper is ready to
accept commands.  This might lead to flaky tests.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: David Turner <dturner@twopensource.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

2 files changed, 10 insertions, 2 deletions

diff --git a/Documentation/git-index-helper.txt b/Documentation/git-index-helper.txt
index ca5a9dec7f..228b1df511 100644
--- a/Documentation/git-index-helper.txt
+++ b/Documentation/git-index-helper.txt
@@ -34,6 +34,9 @@ OPTIONS
 	for reading an index, but because it will happen in the
 	background, it's not noticable. `--strict` is enabled by default.
 
+--detach::
+	Detach from the shell.
+
 NOTES
 -----
 
diff --git a/index-helper.c b/index-helper.c
index 163586a7f8..eca8ae97aa 100644
--- a/index-helper.c
+++ b/index-helper.c
@@ -17,7 +17,7 @@ struct shm {
 
 static struct shm shm_index;
 static struct shm shm_base_index;
-static int to_verify = 1;
+static int daemonized, to_verify = 1;
 
 static void release_index_shm(struct shm *is)
 {
@@ -36,6 +36,8 @@ static void cleanup_shm(void)
 
 static void cleanup(void)
 {
+	if (daemonized)
+		return;
 	unlink(git_path("index-helper.sock"));
 	cleanup_shm();
 }
@@ -264,7 +266,7 @@ static const char * const usage_text[] = {
 int main(int argc, char **argv)
 {
 	const char *prefix;
-	int idle_in_seconds = 600;
+	int idle_in_seconds = 600, detach = 0;
 	int fd;
 	struct strbuf socket_path = STRBUF_INIT;
 	struct option options[] = {
@@ -272,6 +274,7 @@ int main(int argc, char **argv)
 			    N_("exit if not used after some seconds")),
 		OPT_BOOL(0, "strict", &to_verify,
 			 N_("verify shared memory after creating")),
+		OPT_BOOL(0, "detach", &detach, N_("detach the process")),
 		OPT_END()
 	};
 
@@ -299,6 +302,8 @@ int main(int argc, char **argv)
 		die("--exit-after value must be less than %d seconds",
 		    INT_MAX / 1000);
 
+	if (detach && daemonize(&daemonized))
+		die_errno(_("unable to detach"));
 	loop(fd, idle_in_seconds);
 
 	close(fd);