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

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.

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?

quoted

+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