Re: [PATCH v3 02/12] rerere: convert flags into an enum

[Junio C Hamano <gitster@pobox.com>]

Junio C Hamano <gitster@pobox.com> writes:

> Patrick Steinhardt <ps@pks.im> writes:
>
>>> What BOTH versions lack is an explanation why RERERE_NOAUTOUPDATE is
>>> needed in the first place.  In other words, "How is it different
>>> from the lack of RERERE_AUTOUPDATE bit?" is not answered here.  And
>>> I think that is a lot more important thing to clarify.
>>
>> Heh, in this case _I_ thought that it's implicitly clear from the
>> comment of `RERERE_AUTOUPDATE`: it overrides "rerere.autoUpdate". I
>> figured that updating these comments would cause some discussions, and
>> that's exactly why I didn't dare to update them at all in v1 :)
>
> ;-)

The command line can give us not two (which could be represented
with a single bit) but three choices, (0) the command line has no
preference on --[no-]autoupdate and follow the configured default,
(1) --autoupdate, or (2) --no-autoupdate, and that is exactly why we
have these two independent-looking bits.

But two bits can express another combination (i.e., both bits on),
which probably is invalid.  The underlying OPT_UYN() calls
parse_opt_tertiary() which only chooses between 1 and 2 so we should
be safe on the setting side, but I offhand do not remember if we
detect when both bits are on and BUG() out where we consume the
value.

Thanks.