Re: [PATCH 1/1] Use reverse_commit_list helper function for in-place list reversal

[Jayati Shrivastava <gaurijove@gmail.com>]

This patch addresses https://github.com/gitgitgadget/git/issues/1156 . I have
left builtin/merge.c unmodified since in its case, the original list
is needed separately
from its reverse copy.

On Mon, Mar 14, 2022 at 1:36 PM JAYATI SHRIVASTAVA <gaurijove@gmail.com> wrote:
>
> From: JAYATI SHRIVASTAVA <gaurijove@gmail.com>
>
> Here, a reverse copy of the list is being created by looping and the
> original list is no longer used by the code. Therefore, instead of creating a copy,
> we can reverse the original list in-place using the reverse_commit_list helper
> function a copy.
>
> Signed-off-by: JAYATI SHRIVASTAVA <gaurijove@gmail.com>
> ---
>  sequencer.c | 10 ++++------
>  1 file changed, 4 insertions(+), 6 deletions(-)
>
> diff --git a/sequencer.c b/sequencer.c
> index 35006c0cea..bccbb9e352 100644
> --- a/sequencer.c
> +++ b/sequencer.c
> @@ -3749,7 +3749,7 @@ static int do_merge(struct repository *r,
>         int run_commit_flags = 0;
>         struct strbuf ref_name = STRBUF_INIT;
>         struct commit *head_commit, *merge_commit, *i;
> -       struct commit_list *bases, *j, *reversed = NULL;
> +       struct commit_list *bases, *j;
>         struct commit_list *to_merge = NULL, **tail = &to_merge;
>         const char *strategy = !opts->xopts_nr &&
>                 (!opts->strategy ||
> @@ -3984,9 +3984,7 @@ static int do_merge(struct repository *r,
>                       git_path_merge_head(r), 0);
>         write_message("no-ff", 5, git_path_merge_mode(r), 0);
>
> -       for (j = bases; j; j = j->next)
> -               commit_list_insert(j->item, &reversed);
> -       free_commit_list(bases);
> +       bases = reverse_commit_list(bases);
>
>         repo_read_index(r);
>         init_merge_options(&o, r);
> @@ -4002,10 +4000,10 @@ static int do_merge(struct repository *r,
>                  * update the index and working copy immediately.
>                  */
>                 ret = merge_ort_recursive(&o,
> -                                         head_commit, merge_commit, reversed,
> +                                         head_commit, merge_commit, bases,
>                                           &i);
>         } else {
> -               ret = merge_recursive(&o, head_commit, merge_commit, reversed,
> +               ret = merge_recursive(&o, head_commit, merge_commit, bases,
>                                       &i);
>         }
>         if (ret <= 0)
> --
> 2.35.1.455.g1a4874565f
>