Re: [PATCH/RFC 5/5] add tests for checking the behaviour of "unset.variable"

From: Matthieu Moy <matthieu.moy@grenoble-inp.fr>
Date: Oct 3, 2014, 07:01 UTC
Message-ID: <vpqeguptz5k.fsf@anie.imag.fr>
In-Reply-To: <xmqqiok2m494.fsf@gitster.dls.corp.google.com>

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

Show 15 quoted lines

> Tanay Abhra <tanayabh@gmail.com> writes:
>
>> I can think of two solutions, one leave it as it is and advertise it to be
>> explicitly typed in the config files at the appropriate position or to change
>> the behavior of unset.variable to unset all matching variables in that file,
>> before and after. We could also change git config --add to append at the end
>> of the file regardless the variable exists or not. Which course of action
>> do you think would be best?
>
> Off the top of my head, from an end-user's point of view, something
> like this would give a behaviour that is at least understandable:
>
>  (1) forbid "git config" command line from touching "unset.var", as
>      there is no way for a user to control where a new unset.var
>      goes.  And

Well, the normal use-case for unset.variable is to put it in a local config file, to unset a variable set in another, lower-priority file.

This common use-case works with the command-line "git config", and it would be a pity to forbid the common use-case because of a particular, unusual case.

>  (2) When adding or appending section.var (it may also apply to
>      removing one--you need to think about it deeper), ignore
>      everything that comes before the last appearance of "unset.var"
>      that unsets the "section.var" variable.

That would probably be the best option from a user's point of view, but I'd say the implementation complexity is not worth the trouble.

Show 12 quoted lines

> Alternatively, if the syntax to unset a "section.var" were not
>
> 	[unset]
>         	variable = section.var
>
> but rather
>
> 	[section]
> 		! variable
>
> or soemthing, then the current "find the section and append at the
> end" code may work as-is.

But that would break backward compatibility rather badly: old git's would stop working completely in repositories using this syntax.

Well, perhaps we can also consider that this is acceptable: just don't use the feature for a few years if you care about backward compatibility.

-- 
Matthieu Moy
http://www-verimag.imag.fr/~moy/