Re: [PATCH v3 0/5] Sparse Index: Integrate with 'git add'

[Elijah Newren <newren@gmail.com>]

On Thu, Jul 29, 2021 at 8:52 AM Derrick Stolee via GitGitGadget
<gitgitgadget@gmail.com> wrote:
>
> This patch series re-submits the 'git add' integration with sparse-index.
> The performance gains are the same as before.
>
> It is based on ds/commit-and-checkout-with-sparse-index.
>
> This series was delayed from its initial submission for a couple reasons.
>
> The first was because it was colliding with some changes in
> mt/add-rm-in-sparse-checkout, so now we are far enough along that that
> branch is in our history and we can work forwards.
>
> The other concern was about how 'git add ' should respond when a path
> outside of the sparse-checkout cone exists. One recommendation (that I am
> failing to find a link to the message, sorry) was to disallow adding files
> that would become index entries with SKIP_WORKTREE on. However, as I worked
> towards that goal I found that change would cause problems for a realistic
> scenario: merge conflicts outside of the sparse-checkout cone.
>
> Update: Elijah points out that the SKIP_WORKTREE bit is removed from
> conflict files, which allows adding the conflicted files without warning.
> (However, we also need to be careful about untracked files, as documented in
> the test added here.)
>
> The first patch of this series adds tests that create merge conflicts
> outside of the sparse cone and then presents different ways a user could
> resolve the situation. We want all of them to be feasible, and this
> includes:
>
>  1. Reverting the file to a known version in history.
>  2. Adding the file with its contents on disk.
>  3. Moving the file to a new location in the sparse directory.
>
> The one place I did continue to update is 'git add --refresh ' to match the
> behavior added by mt/add-rm-in-sparse-checkout which outputs an error
> message. This happens even when the file exists in the working directory,
> but that seems appropriate enough.
>
>
> Updates in V3
> =============
>
>  * Added disclaimer to the merge-conflict test that this is documenting
>    current behavior, not endorsing it.
>
>  * Added Elijah's reviewed-by. Thanks for the review!

Yep, this one looks ready to merge down to me.  Thanks!

> Thanks, -Stolee
>
> Derrick Stolee (5):
>   t1092: test merge conflicts outside cone
>   add: allow operating on a sparse-only index
>   pathspec: stop calling ensure_full_index
>   add: ignore outside the sparse-checkout in refresh()
>   add: remove ensure_full_index() with --renormalize
>
>  builtin/add.c                            | 15 ++++--
>  pathspec.c                               |  2 -
>  t/t1092-sparse-checkout-compatibility.sh | 67 ++++++++++++++++++++----
>  3 files changed, 70 insertions(+), 14 deletions(-)
>
>
> base-commit: 71e301501c88399711a1bf8515d1747e92cfbb9b
> Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-999%2Fderrickstolee%2Fsparse-index%2Fadd-v3
> Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-999/derrickstolee/sparse-index/add-v3
> Pull-Request: https://github.com/gitgitgadget/git/pull/999
>
> Range-diff vs v2:
>
>  1:  8f2fd9370fe ! 1:  5e96df4df58 t1092: test merge conflicts outside cone
>      @@ Metadata
>        ## Commit message ##
>           t1092: test merge conflicts outside cone
>
>      +    Conflicts can occur outside of the sparse-checkout definition, and in
>      +    that case users might try to resolve the conflicts in several ways.
>      +    Document a few of these ways in a test. Make it clear that this behavior
>      +    is not necessarily the optimal flow, since users can become confused
>      +    when Git deletes these files from the worktree in later commands.
>      +
>      +    Reviewed-by: Elijah Newren <newren@gmail.com>
>           Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
>
>        ## t/t1092-sparse-checkout-compatibility.sh ##
>      @@ t/t1092-sparse-checkout-compatibility.sh: test_expect_success 'merge' '
>         test_all_match git rev-parse HEAD^{tree}
>        '
>
>      ++# NEEDSWORK: This test is documenting current behavior, but that
>      ++# behavior can be confusing to users so there is desire to change it.
>      ++# Right now, users might be using this flow to work through conflicts,
>      ++# so any solution should present advice to users who try this sequence
>      ++# of commands to follow whatever new method we create.
>       +test_expect_success 'merge with conflict outside cone' '
>       + init_repos &&
>       +
>  2:  6e43f118fa0 ! 2:  defab1b86d3 add: allow operating on a sparse-only index
>      @@ Commit message
>           the use of a sparse index. We modify a test in t1092 to demonstrate
>           these changes which will be remedied in future changes.
>
>      +    Reviewed-by: Elijah Newren <newren@gmail.com>
>           Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
>
>        ## builtin/add.c ##
>  3:  2ae91e0af29 ! 3:  9fc4313c889 pathspec: stop calling ensure_full_index
>      @@ Commit message
>           commits. Comparing to the full index case, we see the performance go
>           from 0.33s to 0.05s, an 85% improvement.
>
>      +    Reviewed-by: Elijah Newren <newren@gmail.com>
>           Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
>
>        ## pathspec.c ##
>  4:  a79728d4c64 ! 4:  0ec03ab021d add: ignore outside the sparse-checkout in refresh()
>      @@ Commit message
>           tracked, untracked, or ignored. We simply avoid updating the stat()
>           information because there isn't even an entry that matches the path!
>
>      +    Reviewed-by: Elijah Newren <newren@gmail.com>
>           Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
>
>        ## builtin/add.c ##
>  5:  1543550a4e8 ! 5:  adf5b15ac3d add: remove ensure_full_index() with --renormalize
>      @@ Commit message
>           SKIP_WORKTREE bit, so it will continue to do so with a sparse index
>           because the sparse directory entries also have this bit set.
>
>      +    Reviewed-by: Elijah Newren <newren@gmail.com>
>           Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
>
>        ## builtin/add.c ##
>
> --
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