It is natural to expect that an option defined with OPT_BOOLEAN() could be
used in this way:
int option = -1; /* unspecified */
struct option options[] = {
OPT_BOOLEAN(0, "option", &option, "set option"),
OPT_END()
};
parse_options(ac, av, prefix, options, usage, 0);
if (option < 0)
... do the default thing ...
else if (!option)
... --no-option was given ...
else
... --option was given ...
to easily tell three cases apart:
- There is no mention of the `--option` on the command line;
- The variable is positively set with `--option`; or
- The variable is explicitly negated with `--no-option`.
Unfortunately, this is not the case. OPT_BOOLEAN() increments the variable
every time `--option` is given, and resets it to zero when `--no-option`
is given.
As a first step to remedy this, introduce a true boolean OPT_BOOL(), and
rename OPT_BOOLEAN() to OPT_COUNTUP(). To help transitioning, OPT_BOOLEAN
and OPTION_BOOLEAN are defined as deprecated synonyms to OPT_COUNTUP and
OPTION_COUNTUP respectively.
This is what db7244b (parse-options new features., 2007-11-07) from four
years ago started by marking OPTION_BOOLEAN as "INCR would have been a
better name".
Some existing users do depend on the count-up semantics; for example,
users of OPT__VERBOSE() could use it to raise the verbosity level with
repeated use of `-v` on the command line, but they probably should be
rewritten to use OPT__VERBOSITY() instead these days. I suspect that some
users of OPT__FORCE() may also use it to implement different level of
forcibleness but I didn't check.
On top of this patch, here are the remaining clean-up tasks that other
people can help:
- Look at each hit in "git grep -e OPT_BOOLEAN"; trace all uses of the
value that is set to the underlying variable, and if it can proven that
the variable is only used as a boolean, replace it with OPT_BOOL(). If
the caller does depend on the count-up semantics, replace it with
OPT_COUNTUP() instead.
- Same for OPTION_BOOLEAN; replace it with OPTION_SET_INT and arrange to
set 1 to the variable for a true boolean, and otherwise replace it with
OPTION_COUNTUP.
- Look at each hit in "git grep -e OPT__VERBOSE -e OPT__QUIET" and see if
they can be replaced with OPT__VERBOSITY().
I'll follow this message up with a separate patch as an example.
Signed-off-by: Junio C Hamano <gitster@pobox.com>