Re: [RFC PATCH v3 7/8] Support sparse checkout in unpack_trees() and read-tree

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

On Wed, Aug 12, 2009 at 5:03 AM, <skillzero@gmail.com> wrote:
> On Tue, Aug 11, 2009 at 2:38 PM, Jakub Narebski<jnareb@gmail.com> wrote:
>> skillzero@gmail.com writes:
>>> 2009/8/11 Nguyễn Thái Ngọc Duy <pclouds@gmail.com>:
>>
>>> > [1] .git/info/sparse has the same syntax as .git/info/exclude. Files
>>> > that match the patterns will be set as CE_VALID.
>>>
>>> Does this mean it will only support excluding paths you don't want
>>> rather than letting you only include paths you do want?
>>
>> Errr... what I read is that paths set by .git/info/sparse would be
>> excluded from checkout (marked as assume-unchanged / CE_VALID).
>>
>> But if it is the same mechanism as gitignore, then you can use !
>> prefix to set files (patterns) to include, e.g.
>>
>>  !Documentation/
>>  *
>>
>> (I think rules are processed top-down, first matching wins).
>
> I wasn't sure because the .gitignore negation stuff mentions negating
> a previously ignored pattern. But for sparse patterns, there likely
> wouldn't be a previous pattern.

No problem. We put pattern '*' at top (match everything). Previous
pattern issue solved.

> Include patterns are a little
> different in that if there are no include patterns (but maybe some
> exclude patterns), I think the expectation is that everything will be
> included (minus excludes), but if you have some include patterns then
> only those paths will be included (minus any excludes).

Let's say you want to include foo/ and bar/ only, this should work:

*
!foo/
!bar/

The evaluating order is from bottom up. When it first matches 'bar/',
because it a negate pattern, it returns "no don't match" and stops.
When it matches neither foo/ nor bar/ then it will be caught by '*'
and return "yes it matches" - that means "ignored" from checkout area.
In the end only foo/* and bar/* survive.

I think it's as easy as writing exclude patterns once you figure out '*'.
-- 
Duy