Re: [PATCH v2] pack-refs: fail on falsely sorted packed-refs

From: Max Kirillov <max@max630.net>
Date: Feb 13, 2019, 04:23 UTC
Message-ID: <20190213042307.GA3064@jessie.local>
In-Reply-To: <CAMy9T_EX_L80-V4zD626nFCxw6qa90+pZwcbd6wHw9ZHcj2rNA@mail.gmail.com>

On Mon, Feb 11, 2019 at 08:24:46PM +0100, Michael Haggerty wrote:

> The change to `write_with_updates()` doesn't only affect `pack-refs`.
> That function is also called when the `packed-refs` file has to be
> rewritten when a packed reference is deleted. This is another thing
> that you could test.

Ok, I'll check ti and add to the tests.

Show 7 quoted lines

> But that also means that fairly common commands like `git branch -d`
> could be slowed down by this change. I doubt that the slowdown is
> prohibitive, but it would be great to see numbers to prove it. For
> example, create a repository with a lot (say 10000) references, pack
> them, then run `git branch -d` to delete one of them. Benchmark that
> once with master and once with your modification and document the
> difference.

At my hardware, with 1M references, "branch -d" takes 0.31s of user time before change vs 0.38 after change. Should I mention it in the commit message?

Show 8 quoted lines

>> +test_expect_success 'off-order branch not found' '
>> +       test_must_fail git show-ref --verify --quiet refs/heads/b00
>> +'
> 
> I don't think that the above test makes sense. We don't *guarantee*
> that an out-of-order reference won't be found. That is an
> implementation detail that we are free to change. I think that it
> would be OK to just omit this test.

Thanks, will remove this one