Re: [PATCH 3/2] dir.c: fix dir re-inclusion rules with "NODIR" and "MUSTBEDIR"

From: Duy Nguyen <pclouds@gmail.com>
Date: Mar 19, 2016, 01:03 UTC
Message-ID: <CACsJy8BBwiH9YtDUZRYwHm4t2ou84B6Ltx37ruXkM-vDoSGG9A@mail.gmail.com>
In-Reply-To: <xmqqa8lvr7ix.fsf@gitster.mtv.corp.google.com>

On Sat, Mar 19, 2016 at 1:00 AM, Junio C Hamano <gitster@pobox.com> wrote:

Show 23 quoted lines

> What is the ultimate goal of nd/exclusion-regression-fix topic over
> the behaviour before 2.7.0 and after 2.7.1 (there was a regression
> in 2.7.0 that was reverted in 2.7.1)?  From the cover letter of the
> series:
>
>     Take one was bad and reverted in commit 8c72236. Take two provides a
>     more complete solution to the pair of rules
>
>       exclude/this
>       !exclude/this/except/this
>
>     3/4 should do a better job at stopping regressions in take 1. 4/4
>     provides the solution. I think I have tested (and wrote tests) for all
>     the cases I can imagine.
>
> "solution to the pair of rules" hints there are some problem in the
> pair of rules, without stating what it is trying to solve.
>
> Isn't the root cause of the issue that treat_one_path() when
> deciding if it is worth descending into a directory check if the
> directory itself is excluded and returns path_excluded, even if some
> paths inside it may have a countermanding ! entries that would match
> them?  What if we change that part smarter and allow it to descend?

That's the easy part, detecting a pair and continue descending. The problem is after you descend, exclude engine may return contradicting results on old patterns. It's the same thing that 3/2 describes (after you change patterns from "!dir\ndir/file2" to "dir\n!dir/file2").

-- 
Duy