[PATCH/RFC 2/3] builtin-fetch: add --dry-run option

[Jay Soffian <jaysoffian@gmail.com>]

Teach fetch --dry-run. Unfortunately OPT__DRY_RUN() cannot be used as fetch
already uses "-n" for something else.
---
 builtin-fetch.c |   10 +++++++---
 1 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/builtin-fetch.c b/builtin-fetch.c
index cb48c57..985b36b 100644
--- a/builtin-fetch.c
+++ b/builtin-fetch.c
@@ -23,7 +23,7 @@ enum {
 	TAGS_SET = 2
 };
 
-static int append, force, keep, update_head_ok, verbosity;
+static int append, dry_run, force, keep, update_head_ok, verbosity;
 static int tags = TAGS_DEFAULT;
 static const char *depth;
 static const char *upload_pack;
@@ -42,6 +42,8 @@ static struct option builtin_fetch_options[] = {
 		    "fetch all tags and associated objects", TAGS_SET),
 	OPT_SET_INT('n', NULL, &tags,
 		    "do not fetch all tags (--no-tags)", TAGS_UNSET),
+	OPT_BOOLEAN(0, "dry-run", &dry_run,
+		    "dry run"),
 	OPT_BOOLEAN('k', "keep", &keep, "keep downloaded pack"),
 	OPT_BOOLEAN('u', "update-head-ok", &update_head_ok,
 		    "allow updating of HEAD ref"),
@@ -178,6 +180,8 @@ static int s_update_ref(const char *action,
 	char *rla = getenv("GIT_REFLOG_ACTION");
 	static struct ref_lock *lock;
 
+	if (dry_run)
+		return 0;
 	if (!rla)
 		rla = default_rla.buf;
 	snprintf(msg, sizeof(msg), "%s: %s", rla, action);
@@ -303,7 +307,7 @@ static int store_updated_refs(const char *raw_url, const char *remote_name,
 	char note[1024];
 	const char *what, *kind;
 	struct ref *rm;
-	char *url, *filename = git_path("FETCH_HEAD");
+	char *url, *filename = dry_run ? "/dev/null" : git_path("FETCH_HEAD");
 
 	fp = fopen(filename, "a");
 	if (!fp)
@@ -586,7 +590,7 @@ static int do_fetch(struct transport *transport,
 		die("Don't know how to fetch from %s", transport->url);
 
 	/* if not appending, truncate FETCH_HEAD */
-	if (!append) {
+	if (!append && !dry_run) {
 		char *filename = git_path("FETCH_HEAD");
 		FILE *fp = fopen(filename, "w");
 		if (!fp)
-- 
1.6.4.2