Re: [RFC PATCH v2 3/4] unpack_trees(): add support for sparse checkout

[Nguyen Thai Ngoc Duy <pclouds@gmail.com>]

2009/8/10 Johannes Schindelin <Johannes.Schindelin@gmx.de>:
> Hi,
>
> On Mon, 10 Aug 2009, Nguyễn Thái Ngọc Duy wrote:
>
>> This patch teaches unpack_trees() to checkout/remove entries on working
>> directories appropriately when sparse checkout area is changed. Hook
>> "sparse" is needed to help determine which entry will be checked out,
>> which will not be.
>>
>> When the hook is run, it is prepared with a pseudo index. The hook then
>> can use "git update-index --[no-]assume-unchanged" to manipulate the
>> index. It should not do anything else on the index. Assume unchanged
>> information from the index will be used to shape working directory.
>
> If I understand correctly, the purpose of the hook is to allow the user to
> mark something as unwanted preemptively, right?
>
> If that is the sole reason for the hook, would it not be better to add
> support for a file .git/info/sparse which has the same syntax as
> .git/info/exclude, and which is used to determine if an
> added/modified/deleted file is supposed to be in the "sparse" area or not?
>
> Something like
>
>        *
>        !/Documentation/
>
> comes to mind.

That was what the original series was about (although I used git
config instead of .git/info/sparse). The hook has two advantages:

 - flexibility: you can set things differently based on branch, for
example, or filter files based on certain file content.
 - less code bloat (and less intrusive too), compare ~1000 lines of
change of the original series with this series.
-- 
Duy