Re: [PATCH 08/10] pathspec: stop calling ensure_full_index

[Elijah Newren <newren@gmail.com>]

On Tue, Apr 13, 2021 at 7:01 AM Derrick Stolee via GitGitGadget
<gitgitgadget@gmail.com> wrote:
>
> From: Derrick Stolee <dstolee@microsoft.com>
>
> The add_pathspec_matches_against_index() focuses on matching a pathspec
> to file entries in the index. This already works correctly for its only
> use: checking if untracked files exist in the index.
>
> The compatibility checks in t1092 already test that 'git add <dir>'
> works for a directory outside of the sparse cone. That provides coverage
> for removing this guard.
>
> This finalizes our ability to run 'git add .' without expanding a sparse
> index to a full one. This is evidenced by an update to t1092 and by
> these performance numbers for p2000-sparse-operations.sh:
>
> Test                                    HEAD~1            HEAD
> --------------------------------------------------------------------------------
> 2000.10: git add . (full-index-v3)      1.37(1.02+0.18)   1.38(1.01+0.20) +0.7%
> 2000.11: git add . (full-index-v4)      1.26(1.00+0.15)   1.27(0.99+0.17) +0.8%
> 2000.12: git add . (sparse-index-v3)    2.39(2.29+0.14)   0.06(0.05+0.07) -97.5%
> 2000.13: git add . (sparse-index-v4)    2.42(2.32+0.14)   0.06(0.05+0.06) -97.5%
>
> While the 97% improvement is shown by the test results, it is worth
> noting that expanding the sparse index was adding overhead in previous
> commits. Comparing to the full index case, we see the performance go
> from 1.27s to 0.06s, a 95% improvement.

This is awesome.  :-)

>
> Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
> ---
>  pathspec.c                               | 2 --
>  t/t1092-sparse-checkout-compatibility.sh | 6 ++++++
>  2 files changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/pathspec.c b/pathspec.c
> index 54813c0c4e8e..b51b48471fe6 100644
> --- a/pathspec.c
> +++ b/pathspec.c
> @@ -37,8 +37,6 @@ void add_pathspec_matches_against_index(const struct pathspec *pathspec,
>                         num_unmatched++;
>         if (!num_unmatched)
>                 return;
> -       /* TODO: audit for interaction with sparse-index. */
> -       ensure_full_index(istate);
>         for (i = 0; i < istate->cache_nr; i++) {
>                 const struct cache_entry *ce = istate->cache[i];
>                 if (sw_action == PS_IGNORE_SKIP_WORKTREE && ce_skip_worktree(ce))
> diff --git a/t/t1092-sparse-checkout-compatibility.sh b/t/t1092-sparse-checkout-compatibility.sh
> index c210dba78067..738013b00191 100755
> --- a/t/t1092-sparse-checkout-compatibility.sh
> +++ b/t/t1092-sparse-checkout-compatibility.sh
> @@ -471,6 +471,12 @@ test_expect_success 'sparse-index is not expanded' '
>         echo >>sparse-index/extra.txt &&
>         GIT_TRACE2_EVENT="$(pwd)/trace2.txt" GIT_TRACE2_EVENT_NESTING=10 \
>                 git -C sparse-index add extra.txt &&
> +       test_region ! index ensure_full_index trace2.txt &&
> +
> +       rm trace2.txt &&
> +       echo >>sparse-index/untracked.txt &&
> +       GIT_TRACE2_EVENT="$(pwd)/trace2.txt" GIT_TRACE2_EVENT_NESTING=10 \
> +               git -C sparse-index add . &&
>         test_region ! index ensure_full_index trace2.txt
>  '
>
> --
> gitgitgadget
>