Re: [PATCH v3 08/21] Documentation/git-update-index: talk about core.splitIndex config var

[Christian Couder <christian.couder@gmail.com>]

On Mon, Jan 9, 2017 at 12:18 PM, Duy Nguyen <pclouds@gmail.com> wrote:
> On Sun, Jan 8, 2017 at 4:38 AM, Junio C Hamano <gitster@pobox.com> wrote:
>> Christian Couder <christian.couder@gmail.com> writes:
>>
>>> It feels strange that when I do things one way, you suggest another
>>> way, and the next time in a similar situation when I do things the way
>>> you suggested previously, then you suggest the way I did it initially
>>> the first time...
>>
>> Perhaps because neither is quite satisfactory and I am being forced
>> to choose between the two unsatifactory designs?  In any case, I
>> mostly am and was pointing out the issues and not saying the other
>> one is the most preferred solution in these threads.
>>
>> I think there should just be one authoritative source of the truth,
>
> Either that, or we make sure all sources of truth are consistent. In
> this case, 'update --split-index' could update core.splitIndex if it
> finds that the config tells a different story. As a plumbing though, I
> rather leave update-index do simple things, even if it means the user
> has to clean up after it (or before it) with "git config -unset
> core.splitIndex". Another option is refuse to execute --split-index in
> the presence of (conflicting) core.splitIndex. We kind of force the
> user to keep all sources of truth consistent this way while leaving a
> back door ("git -c core.splitIndex= update-index") for those who need
> tools to recover from a bad case.
>
>> and I have always thought it should be the bit set in the index file
>> when the command line option is used, because that was the way the
>> feature was introduced first and I am superstitious about end-user
>> inertia.  And from that point of view, no matter how you make this
>> new "config" thing interact with it, it would always give a strange
>> and unsatifactory end-user experience, at least to me.
>>
>> Perhaps we should declare that config will be the one and only way
>> in the future and start deprecating the command line option way.
>> That will remove the need for two to interact with each other.

That would be my preferred solution as I think it is the simplest in
the end for users.
Also, as Duy wrote above, one can always use something like "git -c
core.splitIndex= ...", which by the way can work for any command, not
just "update-index".

Anyway we would have to introduce core.splitIndex first, and it
wouldn't make sense to have a different behavior between
--[no-]split-index and --[no-]untracked-cache in the meantime before
they are deprecated and eventually removed.

So let's just go with the implementation in this series, which is
similar to --[no-]untracked-cache, and let's plan to deprecate
--[no-]split-index and --[no-]untracked-cache in a later patch series.