[PATCH] Make git-update-cache --refresh fail if update/merge needed.

Scripts may find it useful if they do not have to parse the
output from the command but just can rely on its exit status.

Earlier both Linus and myself thought this would be necessary to
make git-prune-script safer but it turns out that the issue was
somewhere else and not related to what this patch addresses.

Signed-off-by: Junio C Hamano <junkio@cox.net>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

update-cache.c

@@ -212,15 +212,17 @@ static struct cache_entry *refresh_entry(struct cache_entry *ce)
 	return updated;
 }
 
-static void refresh_cache(void)
+static int refresh_cache(void)
 {
 	int i;
+	int has_errors = 0;
 
 	for (i = 0; i < active_nr; i++) {
 		struct cache_entry *ce, *new;
 		ce = active_cache[i];
 		if (ce_stage(ce)) {
 			printf("%s: needs merge\n", ce->name);
+			has_errors = 1;
 			while ((i < active_nr) &&
 			       ! strcmp(active_cache[i]->name, ce->name))
 				i++;
@@ -230,12 +232,15 @@ static void refresh_cache(void)
 
 		new = refresh_entry(ce);
 		if (IS_ERR(new)) {
-			if (!(not_new && PTR_ERR(new) == -ENOENT))
+			if (!(not_new && PTR_ERR(new) == -ENOENT)) {
 				printf("%s: needs update\n", ce->name);
+				has_errors = 1;
+			}
 			continue;
 		}
 		active_cache[i] = new;
 	}
+	return has_errors;
 }
 
 /*
@@ -307,7 +312,7 @@ static void remove_lock_file_on_signal(int signo)
 
 int main(int argc, char **argv)
 {
-	int i, newfd, entries;
+	int i, newfd, entries, has_errors = 0;
 	int allow_options = 1;
 	static char lockfile[MAXPATHLEN+1];
 	const char *indexfile = get_index_file();
@@ -343,7 +348,7 @@ int main(int argc, char **argv)
 				continue;
 			}
 			if (!strcmp(path, "--refresh")) {
-				refresh_cache();
+				has_errors |= refresh_cache();
 				continue;
 			}
 			if (!strcmp(path, "--cacheinfo")) {
@@ -369,5 +374,5 @@ int main(int argc, char **argv)
 		die("Unable to write new cachefile");
 
 	lockfile_name = NULL;
-	return 0;
+	return has_errors;
 }