cherry-pick: handle "-" after parsing options

Currently, we only try converting argv[1] from "-" into "@{-1}".  This
means we do not notice "-" when used together with an option.  Worse,
when "git cherry-pick" is run with no options, we segfault.  Fix this
by doing the substitution after we have checked that there is
something in argv to cherry-pick and know any remaining options are
meant for the revision-listing machinery.

This still does not handle "-" after the first non-cherry-pick option.
For example,

	git cherry-pick foo~2 - bar~5

and

	git cherry-pick --no-merges -

will still dump usage.

Reported-by: Stefan Beller <stefanbeller@googlemail.com>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>

builtin/revert.c

@@ -198,6 +198,8 @@ static void parse_args(int argc, const char **argv, struct replay_opts *opts)
 		opts->revs->no_walk = REVISION_WALK_NO_WALK_UNSORTED;
 		if (argc < 2)
 			usage_with_options(usage_str, options);
+		if (!strcmp(argv[1], "-"))
+			argv[1] = "@{-1}";
 		memset(&s_r_opt, 0, sizeof(s_r_opt));
 		s_r_opt.assume_dashdash = 1;
 		argc = setup_revisions(argc, argv, opts->revs, &s_r_opt);
@@ -232,8 +234,6 @@ int cmd_cherry_pick(int argc, const char **argv, const char *prefix)
 	memset(&opts, 0, sizeof(opts));
 	opts.action = REPLAY_PICK;
 	git_config(git_default_config, NULL);
-	if (!strcmp(argv[1], "-"))
-		argv[1] = "@{-1}";
 	parse_args(argc, argv, &opts);
 	res = sequencer_pick_revisions(&opts);
 	if (res < 0)

t/t3501-revert-cherry-pick.sh

@@ -129,4 +129,16 @@ test_expect_success 'cherry-pick "-" is meaningless without checkout' '
 	)
 '
 
+test_expect_success 'cherry-pick "-" works with arguments' '
+	git checkout -b side-branch &&
+	test_commit change actual change &&
+	git checkout master &&
+	git cherry-pick -s - &&
+	echo "Signed-off-by: C O Mitter <committer@example.com>" >expect &&
+	git cat-file commit HEAD | grep ^Signed-off-by: >signoff &&
+	test_cmp expect signoff &&
+	echo change >expect &&
+	test_cmp expect actual
+'
+
 test_done