parse-opt: bring PARSE_OPT_HIDDEN and NONEG to git-rev-parse --parseopt

Signed-off-by: Pierre Habouzit <madcoder@debian.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/git-rev-parse.txt

@@ -325,7 +325,7 @@ The lines after the separator describe the options.
 Each line of options has this format:
 
 ------------
-<opt_spec><arg_spec>? SP+ help LF
+<opt_spec><flags>* SP+ help LF
 ------------
 
 `<opt_spec>`::
@@ -334,10 +334,17 @@ Each line of options has this format:
 	is necessary. `h,help`, `dry-run` and `f` are all three correct
 	`<opt_spec>`.
 
-`<arg_spec>`::
-	an `<arg_spec>` tells the option parser if the option has an argument
-	(`=`), an optional one (`?` though its use is discouraged) or none
-	(no `<arg_spec>` in that case).
+`<flags>`::
+	`<flags>` are of `*`, `=`, `?` or `!`.
+	* Use `=` if the option takes an argument.
+
+	* Use `?` to mean that the option is optional (though its use is discouraged).
+
+	* Use `*` to mean that this option should not be listed in the usage
+	  generated for the `-h` argument. It's shown for `--help-all` as
+	  documented in linkgit:gitcli[5].
+
+	* Use `!` to not make the corresponding negated long option available.
 
 The remainder of the line, after stripping the spaces, is used
 as the help associated to the option.

builtin-rev-parse.c

@@ -322,18 +322,24 @@ static int cmd_parseopt(int argc, const char **argv, const char *prefix)
 		o->type = OPTION_CALLBACK;
 		o->help = xstrdup(skipspaces(s));
 		o->value = &parsed;
+		o->flags = PARSE_OPT_NOARG;
 		o->callback = &parseopt_dump;
-		switch (s[-1]) {
-		case '=':
-			s--;
-			break;
-		case '?':
-			o->flags = PARSE_OPT_OPTARG;
-			s--;
-			break;
-		default:
-			o->flags = PARSE_OPT_NOARG;
-			break;
+		while (s > sb.buf && strchr("*=?!", s[-1])) {
+			switch (*--s) {
+			case '=':
+				o->flags &= ~PARSE_OPT_NOARG;
+				break;
+			case '?':
+				o->flags &= ~PARSE_OPT_NOARG;
+				o->flags |= PARSE_OPT_OPTARG;
+				break;
+			case '!':
+				o->flags |= PARSE_OPT_NONEG;
+				break;
+			case '*':
+				o->flags |= PARSE_OPT_HIDDEN;
+				break;
+			}
 		}
 
 		if (s - sb.buf == 1) /* short option only */