Merge branch 'jc/parseopt-command-modes'

Many commands use --dashed-option as a operation mode selector
(e.g. "git tag --delete") that the user can use at most one
(e.g. "git tag --delete --verify" is a nonsense) and you cannot
negate (e.g. "git tag --no-delete" is a nonsense).  Make it easier
for users of parse_options() to enforce these restrictions.

* jc/parseopt-command-modes:
  tag: use OPT_CMDMODE
  parse-options: add OPT_CMDMODE()

3 files changed, 68 insertions, 20 deletions

diff --git a/builtin/tag.c b/builtin/tag.c
index af3af3f64..d8ae5aae2 100644
--- a/builtin/tag.c
+++ b/builtin/tag.c
@@ -436,18 +436,18 @@ int cmd_tag(int argc, const char **argv, const char *prefix)
 	struct ref_lock *lock;
 	struct create_tag_options opt;
 	char *cleanup_arg = NULL;
-	int annotate = 0, force = 0, lines = -1, list = 0,
-		delete = 0, verify = 0;
+	int annotate = 0, force = 0, lines = -1;
+	int cmdmode = 0;
 	const char *msgfile = NULL, *keyid = NULL;
 	struct msg_arg msg = { 0, STRBUF_INIT };
 	struct commit_list *with_commit = NULL;
 	struct option options[] = {
-		OPT_BOOLEAN('l', "list", &list, N_("list tag names")),
+		OPT_CMDMODE('l', "list", &cmdmode, N_("list tag names"), 'l'),
 		{ OPTION_INTEGER, 'n', NULL, &lines, N_("n"),
 				N_("print <n> lines of each tag message"),
 				PARSE_OPT_OPTARG, NULL, 1 },
-		OPT_BOOLEAN('d', "delete", &delete, N_("delete tags")),
-		OPT_BOOLEAN('v', "verify", &verify, N_("verify tags")),
+		OPT_CMDMODE('d', "delete", &cmdmode, N_("delete tags"), 'd'),
+		OPT_CMDMODE('v', "verify", &cmdmode, N_("verify tags"), 'v'),
 
 		OPT_GROUP(N_("Tag creation options")),
 		OPT_BOOLEAN('a', "annotate", &annotate,
@@ -489,22 +489,19 @@ int cmd_tag(int argc, const char **argv, const char *prefix)
 	}
 	if (opt.sign)
 		annotate = 1;
-	if (argc == 0 && !(delete || verify))
-		list = 1;
+	if (argc == 0 && !cmdmode)
+		cmdmode = 'l';
 
-	if ((annotate || msg.given || msgfile || force) &&
-	    (list || delete || verify))
+	if ((annotate || msg.given || msgfile || force) && (cmdmode != 0))
 		usage_with_options(git_tag_usage, options);
 
-	if (list + delete + verify > 1)
-		usage_with_options(git_tag_usage, options);
 	finalize_colopts(&colopts, -1);
-	if (list && lines != -1) {
+	if (cmdmode == 'l' && lines != -1) {
 		if (explicitly_enable_column(colopts))
 			die(_("--column and -n are incompatible"));
 		colopts = 0;
 	}
-	if (list) {
+	if (cmdmode == 'l') {
 		int ret;
 		if (column_active(colopts)) {
 			struct column_options copts;
@@ -523,9 +520,9 @@ int cmd_tag(int argc, const char **argv, const char *prefix)
 		die(_("--contains option is only allowed with -l."));
 	if (points_at.nr)
 		die(_("--points-at option is only allowed with -l."));
-	if (delete)
+	if (cmdmode == 'd')
 		return for_each_tag_name(argv, delete_tag);
-	if (verify)
+	if (cmdmode == 'v')
 		return for_each_tag_name(argv, verify_tag);
 
 	if (msg.given || msgfile) {
diff --git a/parse-options.c b/parse-options.c
index c2cbca25c..62e9b1cc6 100644
--- a/parse-options.c
+++ b/parse-options.c
@@ -43,8 +43,42 @@ static void fix_filename(const char *prefix, const char **file)
 	*file = xstrdup(prefix_filename(prefix, strlen(prefix), *file));
 }
 
+static int opt_command_mode_error(const struct option *opt,
+				  const struct option *all_opts,
+				  int flags)
+{
+	const struct option *that;
+	struct strbuf message = STRBUF_INIT;
+	struct strbuf that_name = STRBUF_INIT;
+
+	/*
+	 * Find the other option that was used to set the variable
+	 * already, and report that this is not compatible with it.
+	 */
+	for (that = all_opts; that->type != OPTION_END; that++) {
+		if (that == opt ||
+		    that->type != OPTION_CMDMODE ||
+		    that->value != opt->value ||
+		    that->defval != *(int *)opt->value)
+			continue;
+
+		if (that->long_name)
+			strbuf_addf(&that_name, "--%s", that->long_name);
+		else
+			strbuf_addf(&that_name, "-%c", that->short_name);
+		strbuf_addf(&message, ": incompatible with %s", that_name.buf);
+		strbuf_release(&that_name);
+		opterror(opt, message.buf, flags);
+		strbuf_release(&message);
+		return -1;
+	}
+	return opterror(opt, ": incompatible with something else", flags);
+}
+
 static int get_value(struct parse_opt_ctx_t *p,
-		     const struct option *opt, int flags)
+		     const struct option *opt,
+		     const struct option *all_opts,
+		     int flags)
 {
 	const char *s, *arg;
 	const int unset = flags & OPT_UNSET;
@@ -83,6 +117,16 @@ static int get_value(struct parse_opt_ctx_t *p,
 		*(int *)opt->value = unset ? 0 : opt->defval;
 		return 0;
 
+	case OPTION_CMDMODE:
+		/*
+		 * Giving the same mode option twice, although is unnecessary,
+		 * is not a grave error, so let it pass.
+		 */
+		if (*(int *)opt->value && *(int *)opt->value != opt->defval)
+			return opt_command_mode_error(opt, all_opts, flags);
+		*(int *)opt->value = opt->defval;
+		return 0;
+
 	case OPTION_SET_PTR:
 		*(void **)opt->value = unset ? NULL : (void *)opt->defval;
 		return 0;
@@ -143,12 +187,13 @@ static int get_value(struct parse_opt_ctx_t *p,
 
 static int parse_short_opt(struct parse_opt_ctx_t *p, const struct option *options)
 {
+	const struct option *all_opts = options;
 	const struct option *numopt = NULL;
 
 	for (; options->type != OPTION_END; options++) {
 		if (options->short_name == *p->opt) {
 			p->opt = p->opt[1] ? p->opt + 1 : NULL;
-			return get_value(p, options, OPT_SHORT);
+			return get_value(p, options, all_opts, OPT_SHORT);
 		}
 
 		/*
@@ -177,6 +222,7 @@ static int parse_short_opt(struct parse_opt_ctx_t *p, const struct option *optio
 static int parse_long_opt(struct parse_opt_ctx_t *p, const char *arg,
                           const struct option *options)
 {
+	const struct option *all_opts = options;
 	const char *arg_end = strchr(arg, '=');
 	const struct option *abbrev_option = NULL, *ambiguous_option = NULL;
 	int abbrev_flags = 0, ambiguous_flags = 0;
@@ -253,7 +299,7 @@ is_abbreviated:
 				continue;
 			p->opt = rest + 1;
 		}
-		return get_value(p, options, flags ^ opt_flags);
+		return get_value(p, options, all_opts, flags ^ opt_flags);
 	}
 
 	if (ambiguous_option)
@@ -265,18 +311,20 @@ is_abbreviated:
 			(abbrev_flags & OPT_UNSET) ?  "no-" : "",
 			abbrev_option->long_name);
 	if (abbrev_option)
-		return get_value(p, abbrev_option, abbrev_flags);
+		return get_value(p, abbrev_option, all_opts, abbrev_flags);
 	return -2;
 }
 
 static int parse_nodash_opt(struct parse_opt_ctx_t *p, const char *arg,
 			    const struct option *options)
 {
+	const struct option *all_opts = options;
+
 	for (; options->type != OPTION_END; options++) {
 		if (!(options->flags & PARSE_OPT_NODASH))
 			continue;
 		if (options->short_name == arg[0] && arg[1] == '\0')
-			return get_value(p, options, OPT_SHORT);
+			return get_value(p, options, all_opts, OPT_SHORT);
 	}
 	return -2;
 }
diff --git a/parse-options.h b/parse-options.h
index 9b94596e4..f37fc8814 100644
--- a/parse-options.h
+++ b/parse-options.h
@@ -13,6 +13,7 @@ enum parse_opt_type {
 	OPTION_COUNTUP,
 	OPTION_SET_INT,
 	OPTION_SET_PTR,
+	OPTION_CMDMODE,
 	/* options with arguments (usually) */
 	OPTION_STRING,
 	OPTION_INTEGER,
@@ -130,6 +131,8 @@ struct option {
 #define OPT_BOOL(s, l, v, h)        OPT_SET_INT(s, l, v, h, 1)
 #define OPT_SET_PTR(s, l, v, h, p)  { OPTION_SET_PTR, (s), (l), (v), NULL, \
 				      (h), PARSE_OPT_NOARG, NULL, (p) }
+#define OPT_CMDMODE(s, l, v, h, i) { OPTION_CMDMODE, (s), (l), (v), NULL, \
+				      (h), PARSE_OPT_NOARG|PARSE_OPT_NONEG, NULL, (i) }
 #define OPT_INTEGER(s, l, v, h)     { OPTION_INTEGER, (s), (l), (v), N_("n"), (h) }
 #define OPT_STRING(s, l, v, a, h)   { OPTION_STRING,  (s), (l), (v), (a), (h) }
 #define OPT_STRING_LIST(s, l, v, a, h) \