Re: [PATCH 7/8] builtin/history: split out extended function to create commits

>
> In the next commit we're about to introduce a new command that splits up
> a commit into two. Most of the logic will be shared with rewording
> commits, except that we also need to have control over the parents and
> the old/new trees.
>
> Extract a new function `commit_tree_with_edited_message_ext()` to
> prepare for this commit.

> Signed-off-by: Patrick Steinhardt <ps@pks.im>
> ---
>  builtin/history.c | 67 +++++++++++++++++++++++++++++++++----------------------
>  1 file changed, 40 insertions(+), 27 deletions(-)
>
> diff --git a/builtin/history.c b/builtin/history.c
> index 1cf6c668cf..80726ce14b 100644
> --- a/builtin/history.c
> +++ b/builtin/history.c
> @@ -83,10 +83,13 @@ static int fill_commit_message(struct repository *repo,
>         return 0;
>  }
>
> -static int commit_tree_with_edited_message(struct repository *repo,
> -                                          const char *action,
> -                                          struct commit *original,
> -                                          struct commit **out)
> +static int commit_tree_with_edited_message_ext(struct repository *repo,
> +                                              const char *action,
> +                                              struct commit *commit_with_message,
> +                                              const struct commit_list *parents,
> +                                              const struct object_id *old_tree,
> +                                              const struct object_id *new_tree,
> +                                              struct commit **out)
>  {
>         const char *exclude_gpgsig[] = {
>                 /* We reencode the message, so the encoding needs to be stripped. */
> @@ -100,44 +103,27 @@ static int commit_tree_with_edited_message(struct repository *repo,
>         struct commit_extra_header *original_extra_headers = NULL;
>         struct strbuf commit_message = STRBUF_INIT;
>         struct object_id rewritten_commit_oid;
> -       struct object_id original_tree_oid;
> -       struct object_id parent_tree_oid;
>         char *original_author = NULL;
> -       struct commit *parent;
>         size_t len;
>         int ret;
>
> -       original_tree_oid = repo_get_commit_tree(repo, original)->object.oid;
> -
> -       parent = original->parents ? original->parents->item : NULL;
> -       if (parent) {
> -               if (repo_parse_commit(repo, parent)) {
> -                       ret = error(_("unable to parse parent commit %s"),
> -                                   oid_to_hex(&parent->object.oid));
> -                       goto out;
> -               }
> -
> -               parent_tree_oid = repo_get_commit_tree(repo, parent)->object.oid;
> -       } else {
> -               oidcpy(&parent_tree_oid, repo->hash_algo->empty_tree);
> -       }
> -
>         /* We retain authorship of the original commit. */
> -       original_message = repo_logmsg_reencode(repo, original, NULL, NULL);
> +       original_message = repo_logmsg_reencode(repo, commit_with_message, NULL, NULL);
>         ptr = find_commit_header(original_message, "author", &len);
>         if (ptr)
>                 original_author = xmemdupz(ptr, len);
>         find_commit_subject(original_message, &original_body);
>
> -       ret = fill_commit_message(repo, &parent_tree_oid, &original_tree_oid,
> +       ret = fill_commit_message(repo, old_tree, new_tree,
>                                   original_body, action, &commit_message);
>         if (ret < 0)
>                 goto out;
>
> -       original_extra_headers = read_commit_extra_headers(original, exclude_gpgsig);
> +       original_extra_headers = read_commit_extra_headers(commit_with_message,
> +                                                          exclude_gpgsig);
>
> -       ret = commit_tree_extended(commit_message.buf, commit_message.len, &original_tree_oid,
> -                                  original->parents, &rewritten_commit_oid, original_author,
> +       ret = commit_tree_extended(commit_message.buf, commit_message.len, new_tree,
> +                                  parents, &rewritten_commit_oid, original_author,
>                                    NULL, NULL, original_extra_headers);
>         if (ret < 0)
>                 goto out;
> @@ -151,6 +137,33 @@ static int commit_tree_with_edited_message(struct repository *repo,
>         return ret;
>  }
>
> +static int commit_tree_with_edited_message(struct repository *repo,
> +                                          const char *action,
> +                                          struct commit *original,
> +                                          struct commit **out)
> +{
> +       struct object_id parent_tree_oid;
> +       const struct object_id *tree_oid;
> +       struct commit *parent;
> +
> +       tree_oid = &repo_get_commit_tree(repo, original)->object.oid;
> +
> +       parent = original->parents ? original->parents->item : NULL;
> +       if (parent) {
> +               if (repo_parse_commit(repo, parent)) {
> +                       return error(_("unable to parse parent commit %s"),
> +                                    oid_to_hex(&parent->object.oid));
> +               }
> +
> +               parent_tree_oid = repo_get_commit_tree(repo, parent)->object.oid;
> +       } else {
> +               oidcpy(&parent_tree_oid, repo->hash_algo->empty_tree);
> +       }
> +
> +       return commit_tree_with_edited_message_ext(repo, action, original, original->parents,
> +                                                  &parent_tree_oid, tree_oid, out);
> +}
> +
>  enum ref_action {
>         REF_ACTION_DEFAULT,
>         REF_ACTION_BRANCHES,
>
> --
> 2.53.0.697.g625c4fb2da.dirty
>
>