parse-options: drop parse_opt_unknown_cb()

This low-level callback was introduced in ce564eb (parse-options:
add parse_opt_unknown_cb(), 2016-09-05) so that we could advertise
--indent-heuristic in git-blame's "-h" output, even though the option is
actually handled in parse_revision_opt(). We later stopped doing so in
44ae131 (builtin/blame.c: remove '--indent-heuristic' from usage
string, 2019-10-28).

This is a weird thing to do, and in the intervening years, we've never
used it again. Let's drop the helper in the name of simplicity.

Signed-off-by: Jeff King <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: peff

parse-options-cb.c

@@ -213,21 +213,6 @@ int parse_opt_noop_cb(const struct option *opt, const char *arg, int unset)
 	return 0;
 }
 
-/**
- * Report that the option is unknown, so that other code can handle
- * it. This can be used as a callback together with
- * OPTION_LOWLEVEL_CALLBACK to allow an option to be documented in the
- * "-h" output even if it's not being handled directly by
- * parse_options().
- */
-enum parse_opt_result parse_opt_unknown_cb(struct parse_opt_ctx_t *ctx,
-					   const struct option *opt,
-					   const char *arg, int unset)
-{
-	BUG_ON_OPT_ARG(arg);
-	return PARSE_OPT_UNKNOWN;
-}
-
 /**
  * Recreates the command-line option in the strbuf.
  */

parse-options.h

@@ -348,9 +348,6 @@ int parse_opt_commit(const struct option *, const char *, int);
 int parse_opt_tertiary(const struct option *, const char *, int);
 int parse_opt_string_list(const struct option *, const char *, int);
 int parse_opt_noop_cb(const struct option *, const char *, int);
-enum parse_opt_result parse_opt_unknown_cb(struct parse_opt_ctx_t *ctx,
-					   const struct option *,
-					   const char *, int);
 int parse_opt_passthru(const struct option *, const char *, int);
 int parse_opt_passthru_argv(const struct option *, const char *, int);
 /* value is enum branch_track* */