parse-opt: optionally show "--no-" option string

It is usually better to have positive options, to avoid confusing double
negations.  However, sometimes it is desirable to show the negative option
in the help.

Introduce the flag PARSE_OPT_NEGHELP to do that.

Signed-off-by: Johannes Schindelin <Johannes.Schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/parse-options.c b/parse-options.c
index f7ce523a615b121b8a0825e459c1b75f24253c85..3b71fbb5410332a3f11ca0e450a614b3345a687b 100644 (file)
--- a/parse-options.c
+++ b/parse-options.c
@@ -511,7 +511,7 @@ static int usage_with_options_internal(const char * const *usagestr,
                        continue;
 
                pos = fprintf(stderr, "    ");
-               if (opts->short_name) {
+               if (opts->short_name && !(opts->flags & PARSE_OPT_NEGHELP)) {
                        if (opts->flags & PARSE_OPT_NODASH)
                                pos += fprintf(stderr, "%c", opts->short_name);
                        else
@@ -520,7 +520,9 @@ static int usage_with_options_internal(const char * const *usagestr,
                if (opts->long_name && opts->short_name)
                        pos += fprintf(stderr, ", ");
                if (opts->long_name)
-                       pos += fprintf(stderr, "--%s", opts->long_name);
+                       pos += fprintf(stderr, "--%s%s",
+                               (opts->flags & PARSE_OPT_NEGHELP) ?  "no-" : "",
+                               opts->long_name);
                if (opts->type == OPTION_NUMBER)
                        pos += fprintf(stderr, "-NUM");
 

diff --git a/parse-options.h b/parse-options.h
index aba30671dccd9e90686363a766df3eb25d4a8e20..b32587ad7cbf5ac3923764d68d1ccd197955e660 100644 (file)
--- a/parse-options.h
+++ b/parse-options.h
@@ -36,6 +36,7 @@ enum parse_opt_option_flags {
        PARSE_OPT_LASTARG_DEFAULT = 16,
        PARSE_OPT_NODASH = 32,
        PARSE_OPT_LITERAL_ARGHELP = 64,
+       PARSE_OPT_NEGHELP = 128,
 };
 
 struct option;
@@ -80,6 +81,9 @@ typedef int parse_opt_cb(const struct option *, const char *arg, int unset);
  *   PARSE_OPT_LITERAL_ARGHELP: says that argh shouldn't be enclosed in brackets
  *                             (i.e. '<argh>') in the help message.
  *                             Useful for options with multiple parameters.
+ *   PARSE_OPT_NEGHELP: says that the long option should always be shown with
+ *                             the --no prefix in the usage message. Sometimes
+ *                             useful for users of OPTION_NEGBIT.
  *
  * `callback`::
  *   pointer to the callback to use for OPTION_CALLBACK.