Re: [PATCH v4 3/4] diff: enable and test the sparse index
On 11/22/21 11:47 PM, Elijah Newren wrote:
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> On Mon, Nov 22, 2021 at 2:42 PM Lessley Dennington via GitGitGadget
> <gitgitgadget@gmail.com> wrote:
>>
>> From: Lessley Dennington <lessleydennington@gmail.com>
>>
>> Enable the sparse index within the 'git diff' command. Its implementation
>> already safely integrates with the sparse index because it shares code
>> with the 'git status' and 'git checkout' commands that were already
>> integrated. For more details see:
>>
>> d76723e (status: use sparse-index throughout, 2021-07-14)
>> 1ba5f45 (checkout: stop expanding sparse indexes, 2021-06-29)
>
> I preferred the references in your v3:
>
> d76723ee53 (status: use sparse-index throughout, 2021-07-14)
> 1ba5f45132 (checkout: stop expanding sparse indexes, 2021-06-29)
>
> because 7-character abbreviations aren't very future proof;
> 10-character seems better to me.
>
> (Very micro nit.)
>
Appreciate the pointer - I'll return to the old formatting for v5.
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>>
>> The most interesting thing to do is to add tests that verify that 'git
>> diff' behaves correctly when the sparse index is enabled. These cases are:
>>
>> 1. The index is not expanded for 'diff' and 'diff --staged'
>> 2. 'diff' and 'diff --staged' behave the same in full checkout, sparse
>> checkout, and sparse index repositories in the following partially-staged
>> scenarios (i.e. the index, HEAD, and working directory differ at a given
>> path):
>> 1. Path is within sparse-checkout cone
>> 2. Path is outside sparse-checkout cone
>> 3. A merge conflict exists for paths outside sparse-checkout cone
>>
>> The `p2000` tests demonstrate a ~44% execution time reduction for 'git
>> diff' and a ~86% execution time reduction for 'git diff --staged' using a
>> sparse index:
>>
>> Test before after
>> -------------------------------------------------------------
>> 2000.30: git diff (full-v3) 0.33 0.34 +3.0%
>> 2000.31: git diff (full-v4) 0.33 0.35 +6.1%
>> 2000.32: git diff (sparse-v3) 0.53 0.31 -41.5%
>> 2000.33: git diff (sparse-v4) 0.54 0.29 -46.3%
>> 2000.34: git diff --cached (full-v3) 0.07 0.07 +0.0%
>> 2000.35: git diff --cached (full-v4) 0.07 0.08 +14.3%
>> 2000.36: git diff --cached (sparse-v3) 0.28 0.04 -85.7%
>> 2000.37: git diff --cached (sparse-v4) 0.23 0.03 -87.0%
>>
>> Co-authored-by: Derrick Stolee <dstolee@microsoft.com>
>> Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
>> Signed-off-by: Lessley Dennington <lessleydennington@gmail.com>
>> ---
>> builtin/diff.c | 5 +++
>> t/perf/p2000-sparse-operations.sh | 2 ++
>> t/t1092-sparse-checkout-compatibility.sh | 46 ++++++++++++++++++++++++
>> 3 files changed, 53 insertions(+)
>>
>> diff --git a/builtin/diff.c b/builtin/diff.c
>> index dd8ce688ba7..fa4683377eb 100644
>> --- a/builtin/diff.c
>> +++ b/builtin/diff.c
>> @@ -437,6 +437,11 @@ int cmd_diff(int argc, const char **argv, const char *prefix)
>>
>> prefix = setup_git_directory_gently(&nongit);
>>
>> + if (!nongit) {
>> + prepare_repo_settings(the_repository);
>> + the_repository->settings.command_requires_full_index = 0;
>> + }
>> +
>> if (!no_index) {
>> /*
>> * Treat git diff with at least one path outside of the
>> diff --git a/t/perf/p2000-sparse-operations.sh b/t/perf/p2000-sparse-operations.sh
>> index bfd332120c8..5cf94627383 100755
>> --- a/t/perf/p2000-sparse-operations.sh
>> +++ b/t/perf/p2000-sparse-operations.sh
>> @@ -113,5 +113,7 @@ test_perf_on_all git checkout -f -
>> test_perf_on_all git reset
>> test_perf_on_all git reset --hard
>> test_perf_on_all git reset -- does-not-exist
>> +test_perf_on_all git diff
>> +test_perf_on_all git diff --cached
>>
>> test_done
>> diff --git a/t/t1092-sparse-checkout-compatibility.sh b/t/t1092-sparse-checkout-compatibility.sh
>> index 44d5e11c762..53524660759 100755
>> --- a/t/t1092-sparse-checkout-compatibility.sh
>> +++ b/t/t1092-sparse-checkout-compatibility.sh
>> @@ -832,6 +832,52 @@ test_expect_success 'sparse-index is not expanded: merge conflict in cone' '
>> )
>> '
>>
>> +test_expect_success 'sparse index is not expanded: diff' '
>> + init_repos &&
>> +
>> + write_script edit-contents <<-\EOF &&
>> + echo text >>$1
>> + EOF
>> +
>> + # Add file within cone
>> + test_sparse_match git sparse-checkout set deep &&
>> + run_on_all ../edit-contents deep/testfile &&
>> + test_all_match git add deep/testfile &&
>> + run_on_all ../edit-contents deep/testfile &&
>> +
>> + test_all_match git diff &&
>> + test_all_match git diff --staged &&
>> + ensure_not_expanded diff &&
>> + ensure_not_expanded diff --staged &&
>> +
>> + # Add file outside cone
>> + test_all_match git reset --hard &&
>> + run_on_all mkdir newdirectory &&
>> + run_on_all ../edit-contents newdirectory/testfile &&
>> + test_sparse_match git sparse-checkout set newdirectory &&
>> + test_all_match git add newdirectory/testfile &&
>> + run_on_all ../edit-contents newdirectory/testfile &&
>> + test_sparse_match git sparse-checkout set &&
>> +
>> + test_all_match git diff &&
>> + test_all_match git diff --staged &&
>> + ensure_not_expanded diff &&
>> + ensure_not_expanded diff --staged &&
>> +
>> + # Merge conflict outside cone
>> + # The sparse checkout will report a warning that is not in the
>> + # full checkout, so we use `run_on_all` instead of
>> + # `test_all_match`
>> + run_on_all git reset --hard &&
>> + test_all_match git checkout merge-left &&
>> + test_all_match test_must_fail git merge merge-right &&
>> +
>> + test_all_match git diff &&
>> + test_all_match git diff --staged &&
>> + ensure_not_expanded diff &&
>> + ensure_not_expanded diff --staged
>
> You've changed some of the --staged to --cached, but based on Junio's
> comments on the previous round, you probably want to convert the
> others too.
> Show 8 quoted lines
>> +'
>> +
>> # NEEDSWORK: a sparse-checkout behaves differently from a full checkout
>> # in this scenario, but it shouldn't.
>> test_expect_success 'reset mixed and checkout orphan' '
>> --
>> gitgitgadget
>>
Lessley Dennington <lessleydennington@gmail.com>