oddballs: send usage() help text to standard output

Using the show_usage_if_asked() helper we introduced earlier, fix
callers of usage() that want to show the help text when explicitly
asked by the end-user.  The help text now goes to the standard
output stream for them.

The callers in this step are oddballs in that their invocations of
usage() are *not* guarded by

	if (argc == 2 && !strcmp(argv[1], "-h")
		usage(...);

There are (unnecessarily) being clever ones that do things like

	if (argc != 2 || !strcmp(argv[1], "-h")
		usage(...);

to say "I know I take only one argument, so argc != 2 is always an
error regardless of what is in argv[].  Ah, by the way, even if argc
is 2, "-h" is a request for usage text, so we do the same".

Some like "git var -h" just do not treat "-h" any specially, and let
it take the same error code paths as a parameter error.

Now we cannot do the same, so these callers are rewrittin to do the
show_usage_and_exit_if_asked() first and then handle the usage error
the way they used to.

Acked-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 6 insertions, 2 deletions

diff --git a/builtin/unpack-file.c b/builtin/unpack-file.c
index 6da2825753..fb5fcbc40a 100644
--- a/builtin/unpack-file.c
+++ b/builtin/unpack-file.c
@@ -26,6 +26,9 @@ static char *create_temp_file(struct object_id *oid)
 	return path;
 }
 
+static const char usage_msg[] =
+"git unpack-file <blob>";
+
 int cmd_unpack_file(int argc,
 		    const char **argv,
 		    const char *prefix UNUSED,
@@ -33,8 +36,9 @@ int cmd_unpack_file(int argc,
 {
 	struct object_id oid;
 
-	if (argc != 2 || !strcmp(argv[1], "-h"))
-		usage("git unpack-file <blob>");
+	show_usage_if_asked(argc, argv, usage_msg);
+	if (argc != 2)
+		usage(usage_msg);
 	if (repo_get_oid(the_repository, argv[1], &oid))
 		die("Not a valid object name %s", argv[1]);