On Sun, Dec 10, 2017 at 3:39 PM, Jeff King <peff@xxxxxxxx> wrote:
> On Sun, Dec 10, 2017 at 09:31:18AM -0500, Jeff King wrote:
>
>> On Sat, Dec 09, 2017 at 09:40:07PM +0100, Christian Couder wrote:
>>
>> > The changes compared to v2 are:
>> >
>> > - s/_val/_arg/ in the name of the functions
>> > - s/val/arg/ in the name of the third argument of the functions
>> > - works with NULL as third argument of the functions
>>
>> This whole series looks OK to me, but this third point made me wonder:
>> what would be the use of allowing NULL for the "arg" parameter?
>>
>> I didn't see any use of this in the series, and I'm having trouble
>> figuring out how it would be useful. E.g., if I do:
>>
>> if (skip_to_optional_arg(arg, "--foo", NULL))
>> ...
>>
>> what can I do in "..."? I know we matched _some_ type of "--foo", but I
>> cannot know whether it was "--foo" or "--foo=bar", nor what "bar" is. It
>> could only be used by some kind of vague validator to say "well, at
>> least this looks like an option that I _could_ parse if I wanted to".
>>
>> So I guess I don't mind it, as it does the most reasonable thing it can
>> when passed NULL, but I would be surprised if we ever actually exercise
>> the code path.
>
> And of course as soon as I sent this, I went back and double-checked.
> And indeed I totally missed this call:
>
> + else if (starts_with(arg, "-B") ||
> + skip_to_optional_arg(arg, "--break-rewrites", NULL)) {
> if ((options->break_opt = diff_scoreopt_parse(arg)) == -1)
Yeah, calls like this were discussed in:
https://public-inbox.org/git/xmqqh8t6o9me.fsf@xxxxxxxxxxxxxxxxxxxxxxxxxxx/
> So that's kind-of weird, because we are parsing "-B", etc, and then
> expecting it to be _reparsed_ by diff_scoreopt_parse. So the two
> callsites must always match. IMHO this ought to do either:
>
> - we should just ask diff_scoreopt_parser to tell us if this was a
> valid option that it understood
>
> or
>
> - parse up to the "=", and then ask the scoreopt parser to parse the
> remainder. This would require us passing 'B'/'C'/'M' to the
> function ourselves, I think that's a better pattern. It means we
> could reuse the parser for things like config values if we wanted to
> (our current diff.renames is a bool, but it would not be
> unreasonable for it to take a score).
>
> None of that is a mess of your creation, though, so I'm OK punting on it
> for now.
Yeah, this could be part of the #leftoverbits.
