Re: [PATCH v4 01/20] sparse-index: design doc and format update

From: Derrick Stolee <stolee@gmail.com>
Date: Mar 29, 2021, 14:32 UTC
Message-ID: <d7a0550b-90e8-fa37-c456-7c70c089dbec@gmail.com>
In-Reply-To: <xmqq8s68oxr4.fsf@gitster.g>

On 3/27/2021 9:47 PM, Junio C Hamano wrote:

Show 16 quoted lines

> SZEDER Gábor <szeder.dev@gmail.com> writes:
> 
>>> +To start, we use a new repository extension, `extensions.sparseIndex`, to
>>> +allow inserting sparse-directory entries into indexes with file format
>>> +versions 2, 3, and 4. This prevents Git versions that do not understand
>>> +the sparse-index from operating on one, but it also prevents other
>>> +operations that do not use the index at all.
>>
>> Why is this not a non-optional index extension?  ...
>> This really should be a non-optional index extension.
> 
> Yeah, the index extension mechanism was designed with optional and
> required kinds because we wanted to support exactly a use case like
> this one.
> 
> Thanks for pointing it out.

Ok, so let me be sure I understand the request, as I believe it is a very good one:

Using a REQUIRED index extension that says "this index has sparse-directory entries" will allow tools that don't touch the index to be compatible with repos using the sparse-index, while also avoiding a new index version.

I'll work on this right away. Thanks! -Stolee