Merge branch 'jc/parseopt-verify-short-name'

Add checks for a common programming mistake to assign the same
short option name to two separate options to help developers.

* jc/parseopt-verify-short-name:
  parse-options: detect attempt to add a duplicate short option name

parse-options.c

@@ -14,8 +14,12 @@ static int parse_options_usage(struct parse_opt_ctx_t *ctx,
 
 int optbug(const struct option *opt, const char *reason)
 {
-	if (opt->long_name)
+	if (opt->long_name) {
+		if (opt->short_name)
+			return error("BUG: switch '%c' (--%s) %s",
+				     opt->short_name, opt->long_name, reason);
 		return error("BUG: option '%s' %s", opt->long_name, reason);
+	}
 	return error("BUG: switch '%c' %s", opt->short_name, reason);
 }
 
@@ -347,12 +351,20 @@ static void check_typos(const char *arg, const struct option *options)
 static void parse_options_check(const struct option *opts)
 {
 	int err = 0;
+	char short_opts[128];
 
+	memset(short_opts, '\0', sizeof(short_opts));
 	for (; opts->type != OPTION_END; opts++) {
 		if ((opts->flags & PARSE_OPT_LASTARG_DEFAULT) &&
 		    (opts->flags & PARSE_OPT_OPTARG))
 			err |= optbug(opts, "uses incompatible flags "
 					"LASTARG_DEFAULT and OPTARG");
+		if (opts->short_name) {
+			if (0x7F <= opts->short_name)
+				err |= optbug(opts, "invalid short name");
+			else if (short_opts[opts->short_name]++)
+				err |= optbug(opts, "short name already used");
+		}
 		if (opts->flags & PARSE_OPT_NODASH &&
 		    ((opts->flags & PARSE_OPT_OPTARG) ||
 		     !(opts->flags & PARSE_OPT_NOARG) ||

t/t1502-rev-parse-parseopt.sh

@@ -19,7 +19,7 @@ sed -e 's/^|//' >expect <<\END_EXPECT
 |    -d, --data[=...]      short and long option with an optional argument
 |
 |Argument hints
-|    -b <arg>              short option required argument
+|    -B <arg>              short option required argument
 |    --bar2 <arg>          long option required argument
 |    -e, --fuz <with-space>
 |                          short and long option required argument
@@ -51,7 +51,7 @@ sed -e 's/^|//' >optionspec <<\EOF
 |d,data?   short and long option with an optional argument
 |
 | Argument hints
-|b=arg     short option required argument
+|B=arg     short option required argument
 |bar2=arg  long option required argument
 |e,fuz=with-space  short and long option required argument
 |s?some    short option optional argument