Re: [PATCH 2/2] diff: teach diff to read gitattribute diff-algorithm

From: Junio C Hamano <gitster@pobox.com>
Date: Feb 7, 2023, 20:47 UTC
Message-ID: <xmqqcz6lyzhw.fsf@gitster.g>
In-Reply-To: <230207.86k00t2owm.gmgdl@evledraar.gmail.com>

Ævar Arnfjörð Bjarmason <avarab@gmail.com> writes:

Show 11 quoted lines

>> From the user's perspective, this is weirdly inconsistent with the
>> existing diff attributes, which would be more like:
>>
>>   # in .gitattributes
>>   *.json diff=json 
>>
>>   # in config
>>   [diff "json"]
>>   algorithm = histogram
>
> That does look more elegant.

We use attributes to define what it is, while configurations are used to define what to do on different things. The separation of attributes and configuration came not from "elegance" or "security" but from a lot more practical reasons.

For a tracked file, the fact that it contains JSON text as payload does not change per user who cloned the project, or per platform the user used to do so. In-tree .gitattributes that the project controls is a perfect way to define what it is for each file.

On the other hand, the diff program suitable to compare two JSON files may vary per platform (your favorite Windows program may not be available to me) and per user (a platform may support more than one and the choice becomes the matter of personal taste).

The security aspect of giving users tighter control over which exact programs are to be run by not allowing the attributes or so called in-tree configuration mechansim is a small bonus that fell out as a consequence.