Re: Parse --o in format-patch

[Jeff King <peff@peff.net>]

On Fri, Jun 28, 2013 at 06:05:00PM +0200, Fredrik Gustafsson wrote:

> I don't quite manage to figure out gits argv parsing and would need some
> help on the way.
> 
> I want:
> git format-patch -o outdir HEAD~
> 
> Work exactly the way it does now, setting output_directory to outdir.
> But I also want
> git format-patch -o HEAD~
> 
> to set output_directory with a NULL value so that I can assign a default
> value to it. Is that even possible with the current argv-parsing implementation?

It's possible to have an "optional" argument by using the
PARSE_OPT_OPTARG flag. However, it is not backwards compatible from the
user's perspective, as they must use the "sticked" form:

  git format-patch -ooutdir ...

to specify the argument. Otherwise, it is not clear in:

  git format-patch -o outdir HEAD~

whether "outdir" is the argument to "-o", or if it is simply the next
argument.

However, if you are just interested in "turning off" a previously given
argument, we usually spell that with the "--no-" prefix to the long
option (e.g., "--no-output-directory" in this case).

I'm not clear how that interacts with your example, though. Your example
tries to use "-o" to set output_directory to NULL. But it is already
NULL if you do not specify any "-o" at all.

-Peff