[PATCH 1/6] parse-options: sanity check PARSE_OPT_NOARG flag

[Jonathan Nieder <jrnieder@gmail.com>]

Some option types cannot use an argument --- boolean options that
would set a bit or flag or increment a counter, for example.  If
configured in the flag word to accept an argument anyway, the result
is an argument that is advertised in "program -h" output only to be
rejected by parse-options::get_value.

Luckily all current users of these option types use PARSE_OPT_NOARG
and do not use PARSE_OPT_OPTARG.  Add a check to ensure that that
remains true.

Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
New patch, preparing for patch 2.  Maybe the check should be
implemented elsewhere (ideally compile time) so all flags can be
checked rather than just the flags that happen to be used in a given
test run.

 parse-options.c |   22 ++++++++++++++++++++++
 1 files changed, 22 insertions(+), 0 deletions(-)

diff --git a/parse-options.c b/parse-options.c
index 0fa79bc..1806bb3 100644
--- a/parse-options.c
+++ b/parse-options.c
@@ -44,6 +44,26 @@ static void fix_filename(const char *prefix, const char **file)
 	*file = xstrdup(prefix_filename(prefix, strlen(prefix), *file));
 }
 
+static void check_flags(const struct option *opt)
+{
+	switch (opt->type) {
+	case OPTION_BOOLEAN:
+	case OPTION_BIT:
+	case OPTION_NEGBIT:
+	case OPTION_SET_INT:
+	case OPTION_SET_PTR:
+	case OPTION_NUMBER:
+		break;
+	default:	/* (usually accepts an argument) */
+		return;
+	}
+	if ((opt->flags & (PARSE_OPT_OPTARG | PARSE_OPT_NOARG)) == PARSE_OPT_NOARG)
+		return;
+	die("BUG: option '-%c%s' should not accept an argument",
+				!opt->short_name ? '-' : opt->short_name,
+				!opt->short_name ? opt->long_name : "");
+}
+
 static int get_value(struct parse_opt_ctx_t *p,
 		     const struct option *opt, int flags)
 {
@@ -51,6 +71,8 @@ static int get_value(struct parse_opt_ctx_t *p,
 	const int unset = flags & OPT_UNSET;
 	int err;
 
+	check_flags(opt);
+
 	if (unset && p->opt)
 		return opterror(opt, "takes no value", flags);
 	if (unset && (opt->flags & PARSE_OPT_NONEG))
-- 
1.7.2.3