patchupdate-ref: Handle large transactions properly

> Test if we can do arbitrary large transactions. Currently this is a known
> bug that we cannot do large transactions, so document it at least in the
> test suite.
>
> Signed-off-by: Stefan Beller <sbeller@google.com>
> ---
>  t/t1400-update-ref.sh | 27 +++++++++++++++++++++++++++
>  1 file changed, 27 insertions(+)
>
> diff --git a/t/t1400-update-ref.sh b/t/t1400-update-ref.sh
> index 6805b9e..a7dd1ff 100755
> --- a/t/t1400-update-ref.sh
> +++ b/t/t1400-update-ref.sh
> @@ -1065,4 +1065,31 @@ test_expect_success 'stdin -z delete refs works with packed and loose refs' '
>         test_must_fail git rev-parse --verify -q $c
>  '
>
> +run_with_limited_open_files () {
> +       (ulimit -n 64 && "$@")
> +}
> +
> +test_lazy_prereq ULIMIT 'run_with_limited_open_files true'
> +
> +test_expect_failure ULIMIT 'large transaction creating branches does not burst open file limit' '
> +(
> +       for i in $(seq 65)
> +               echo "create refs/heads/$i HEAD"
> +       done >large_input &&
> +       git update-ref --stdin <large_input &&
> +       git rev-parse --verify -q refs/heads/65
> +)
> +'
> +
> +test_expect_failure ULIMIT 'large transaction deleting branches does not burst open file limit' '
> +(
> +       for i in $(seq 33)

> +       do
> +               echo "delete refs/heads/$i HEAD"
> +       done >large_input &&
> +       git update-ref --stdin <large_input &&
> +       test_must_fail git rev-parse --verify -q refs/heads/65
> +)
> +'
> +
>  test_done
> --
> 2.2.1.62.g3f15098
>