parse-options: detect attempt to add a duplicate short option name

It is easy to overlook an already assigned single-letter option name
and try to use it for a new one.  Help the developer to catch it
before such a mistake escapes the lab.

This retroactively forbids any short option name (which is defined
to be of type "int") outside the ASCII printable range.  We might
want to do one of two things:

- tighten the type of short_name member to 'char', and further
update optbug() to protect it against doing "'%c'" on a funny
value, e.g. negative or above 127.

- drop the check (even the "duplicate" check) for an option whose
short_name is either negative or above 255, to allow clever folks
to take advantage of the fact that such a short_name cannot be
parsed from the command line and the member can be used to store
some extra information.

Helped-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/parse-options.c b/parse-options.c
index b536896f2689dee23afae7d3a169c065592aaabe..34a15aa73be1f1b68fcde19b5390ea6d2113283e 100644 (file)
--- a/parse-options.c
+++ b/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);
 }
 
@@ -345,12 +349,20 @@ 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) ||

diff --git a/t/t1502-rev-parse-parseopt.sh b/t/t1502-rev-parse-parseopt.sh
index 922423e7d01699b7f56e482c08355942a560671a..ebe7c3b87c34755399495a375b9f4b7e0a45b1c1 100755 (executable)
--- a/t/t1502-rev-parse-parseopt.sh
+++ b/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