[PATCH 2/5] send-pack.c: add an --atomic-push command line argument

@@ -9,7 +9,7 @@ git-send-pack - Push objects over Git protocol to another repository
 SYNOPSIS
 --------
 [verse]
-'git send-pack' [--all] [--dry-run] [--force] [--receive-pack=<git-receive-pack>] [--verbose] [--thin] [<host>:]<directory> [<ref>...]
+'git send-pack' [--all] [--dry-run] [--force] [--receive-pack=<git-receive-pack>] [--verbose] [--thin] [--atomic-push] [<host>:]<directory> [<ref>...]
 
 DESCRIPTION
 -----------

@@ -52,6 +52,11 @@ OPTIONS
 	Send a "thin" pack, which records objects in deltified form based
 	on objects not included in the pack to reduce network traffic.
 
+--atomic-push::
+	With atomic-push all refs are updated in one single atomic transaction.
+	This means that if any of the refs fails then the entire push will
+	fail without changing any refs.
+
 <host>::
 	A remote host to house the repository.  When this
 	part is specified, 'git-receive-pack' is invoked via

@@ -13,7 +13,7 @@
 #include "sha1-array.h"
 
 static const char send_pack_usage[] =
-"git send-pack [--all | --mirror] [--dry-run] [--force] [--receive-pack=<git-receive-pack>] [--verbose] [--thin] [<host>:]<directory> [<ref>...]\n"
+"git send-pack [--all | --mirror] [--dry-run] [--force] [--receive-pack=<git-receive-pack>] [--verbose] [--thin] [--atomic-push] [<host>:]<directory> [<ref>...]\n"
 "  --all and explicit <ref> specification are mutually exclusive.";
 
 static struct send_pack_args args;

@@ -165,6 +165,10 @@ int cmd_send_pack(int argc, const char **argv, const char *prefix)
 				args.use_thin_pack = 1;
 				continue;
 			}
+			if (!strcmp(arg, "--atomic-push")) {
+				args.use_atomic_push = 1;
+				continue;
+			}
 			if (!strcmp(arg, "--stateless-rpc")) {
 				args.stateless_rpc = 1;
 				continue;

@@ -228,6 +228,11 @@ int send_pack(struct send_pack_args *args,
 	if (server_supports("atomic-push"))
 		atomic_push_supported = 1;
 
+	if (args->use_atomic_push && !atomic_push_supported) {
+		fprintf(stderr, "Server does not support atomic-push.");
+		return -1;
+	}
+
 	if (!remote_refs) {
 		fprintf(stderr, "No refs in common and none specified; doing nothing.\n"
 			"Perhaps you should specify a branch such as 'master'.\n");

@@ -272,7 +277,8 @@ int send_pack(struct send_pack_args *args,
 			char *old_hex = sha1_to_hex(ref->old_sha1);
 			char *new_hex = sha1_to_hex(ref->new_sha1);
 			int quiet = quiet_supported && (args->quiet || !args->progress);
-			int atomic_push = atomic_push_supported;
+			int atomic_push = atomic_push_supported &&
+				args->use_atomic_push;
 
 			if (!cmds_sent && (status_report || use_sideband ||
 					   quiet || agent_supported ||

@@ -10,6 +10,7 @@ struct send_pack_args {
 		force_update:1,
 		use_thin_pack:1,
 		use_ofs_delta:1,
+		use_atomic_push:1,
 		dry_run:1,
 		stateless_rpc:1;
 };