Re: [PATCH] Enable git rev-list to parse --quiet

[Junio C Hamano <gitster@pobox.com>]

Junio C Hamano <gitster@pobox.com> writes:

> Nick Andrew <nick@nick-andrew.net> writes:
> ...
>> After fix:
>
> Thanks for noticing, but this replaces one breakage with another.
>
> Your new behaviour is a new "tell me if it is an empty set" option, and it
> means quite different thing from what --quiet does.

And here is how I would do it if I were interested in such a feature.

-- >8 --
rev-list --check-empty

This new option squelches the output entirely and signals if the specified
set is empty by its exit status.  E.g.

    $ git rev-list --check-empty HEAD..HEAD

will exit with a non-zero status, and

    $ git rev-list --check-empty HEAD^..HEAD

will exit with zero status.

---
 builtin-rev-list.c |   15 ++++++++++++++-
 1 files changed, 14 insertions(+), 1 deletions(-)

diff --git a/builtin-rev-list.c b/builtin-rev-list.c
index 507201e..4f9cce9 100644
--- a/builtin-rev-list.c
+++ b/builtin-rev-list.c
@@ -52,6 +52,7 @@ static const char rev_list_usage[] =
 
 static struct rev_info revs;
 
+static int check_empty;
 static int bisect_list;
 static int show_timestamp;
 static int hdr_termination;
@@ -161,6 +162,8 @@ static void show_commit(struct commit *commit)
 
 static void finish_commit(struct commit *commit)
 {
+	if (check_empty)
+		exit(0);
 	if (commit->parents) {
 		free_commit_list(commit->parents);
 		commit->parents = NULL;
@@ -171,6 +174,8 @@ static void finish_commit(struct commit *commit)
 
 static void finish_object(struct object_array_entry *p)
 {
+	if (check_empty)
+		exit(0);
 	if (p->item->type == OBJ_BLOB && !has_sha1_file(p->item->sha1))
 		die("missing blob object '%s'", sha1_to_hex(p->item->sha1));
 }
@@ -593,6 +598,10 @@ int cmd_rev_list(int argc, const char **argv, const char *prefix)
 	for (i = 1 ; i < argc; i++) {
 		const char *arg = argv[i];
 
+		if (!strcmp(arg, "--check-empty")) {
+			check_empty = 1;
+			continue;
+		}
 		if (!strcmp(arg, "--header")) {
 			revs.verbose_header = 1;
 			continue;
@@ -650,6 +659,9 @@ int cmd_rev_list(int argc, const char **argv, const char *prefix)
 
 	if (prepare_revision_walk(&revs))
 		die("revision walk setup failed");
+	if (check_empty)
+		quiet = 1;
+
 	if (revs.tree_objects)
 		mark_edges_uninteresting(revs.commits, &revs, show_edge);
 
@@ -699,6 +711,7 @@ int cmd_rev_list(int argc, const char **argv, const char *prefix)
 	traverse_commit_list(&revs,
 		quiet ? finish_commit : show_commit,
 		quiet ? finish_object : show_object);
-
+	if (check_empty)
+		exit(1);
 	return 0;
 }