From: Junio C Hamano <gitster@pobox.com>
Date: Mon, 06 Jul 2020 06:39:55 GMT
Subject: Re: [PATCH v12 5/5] read-cache: speed up has_dir_name (part 2)
Message-ID: <xmqqr1tp9mf8.fsf@gitster.c.googlers.com>
In-Reply-To: <20200704172708.GC11341@szeder.dev>

SZEDER Gábor <szeder.dev@gmail.com> writes:

>> +				 * last: xxx/yy-file (because '-' sorts before '/')
>> +				 * this: xxx/yy/abc
>
> This is problematic, because the index can already contain 'xxx/yy' as
> a file, when adding 'xxx/yy/abc', but since 'xxx/yy' as a file sorts
> before 'xxx/yy-file', the short-circuiting here doesn't see it and
> thus leaves the d-f collision undetected.  Consequently, even Git
> porcelain commands can create tree objects with duplicate entries, as
> demonstrated in the tests below.

Yeah, the "optimization" is quite bogus.  Thanks for catching it.