Re: [RFC WIP PATCH 2/3] tag: factor out prepare tag template code

[Matheus Tavares Bernardino <matheus.bernardino@usp.br>]

On Tue, Oct 8, 2019 at 3:47 PM Lucas Oshiro <lucasseikioshiro@gmail.com> wrote:
>
> Improve code readability by moving tag body reading to a new function called
> get_tag_body. This function will be used in the following patches to fix the
> --no-edit flag.

This seems to be accidentally duplicated from patch 1/3.

> Enhance legibility by encapsulating code that loads previous tag message
> (if any) in new function prepare_tag_template. This code refactoring is
> part of a series of commits that intend to implement the git tag --amend
> flag and fix the functionality of --no-edit.
>
> Co-authored-by: Bárbara Fernandes <barbara.dcf@gmail.com>
> Helped-by: Matheus Tavares <matheus.bernardino@usp.br>
> Signed-off-by: Lucas Oshiro <lucasseikioshiro@gmail.com>
> Signed-off-by: Bárbara Fernandes <barbara.dcf@gmail.com>

These tags can be re-ordered as I mentioned in patch 1/3, to follow a
chronological order: probably the Helped-by first followed by the
Co-authored-by, Barbara's S-o-B and then your S-o-B.

> ---
>  builtin/tag.c | 65 ++++++++++++++++++++++++++++++---------------------
>  1 file changed, 39 insertions(+), 26 deletions(-)
>
> diff --git a/builtin/tag.c b/builtin/tag.c
> index e1e3549af9..0322bdbdfb 100644
> --- a/builtin/tag.c
> +++ b/builtin/tag.c
> @@ -244,6 +244,43 @@ static const char message_advice_nested_tag[] =
>            "\n"
>            "\tgit tag -f %s %s^{}");
>
> +/*
> + * Write the tag template message with previous tag body (if any) to the given
> + * file.
> + */

Maybe mention that the function creates the file at the given path?

> +static void prepare_tag_template(struct strbuf *given_msg,
> +                                struct create_tag_options *opt,
> +                                struct object_id *prev, char *path,
> +                                const char *tag)

I'm wondering if we could simplify this signature. Maybe we could
resolve whether a message was given at CLI, and if a previous tag
already exists, before getting to this function. This way, 'given_msg'
and 'prev' could be collapsed into a single 'struct strbuf *tag_body'
(and we could replace checking 'opt->message_given' and
'is_null_oid(prev)' by checking if 'tag_body' is not NULL). Then, we
could also pass just the 'cleanup_mode" instead of the whole
'create_tag_options'. Does this makes sense?

> +{
> +       int fd;
> +
> +       fd = open(path, O_CREAT | O_TRUNC | O_WRONLY, 0600);
> +       if (fd < 0)
> +               die_errno(_("could not create file '%s'"), path);
> +
> +       if (opt->message_given) {
> +               write_or_die(fd, given_msg->buf, given_msg->len);
> +               strbuf_reset(given_msg);

I think keeping this reset at create_tag() (right before
lauch_editor() is called and only if 'opt->message_given') makes it
easier to understand what's happening (because there, we are cleaning
the given 'buf' to use it in lauch_editor()). Calling it here may be
misleading as 'given_msg' is not used in this function anymore.

> +       } else if (!is_null_oid(prev)) {
> +               write_tag_body(fd, prev);
> +       } else {
> +               struct strbuf template = STRBUF_INIT;
> +               strbuf_addch(&template, '\n');
> +               if (opt->cleanup_mode == CLEANUP_ALL) {
> +                       strbuf_commented_addf(&template, _(tag_template), tag,
> +                                             comment_line_char);
> +               } else {
> +                       strbuf_commented_addf(&template,
> +                                             _(tag_template_nocleanup), tag,
> +                                             comment_line_char);
> +               }
> +               write_or_die(fd, template.buf, template.len);
> +               strbuf_release(&template);
> +       }
> +       close(fd);
> +}
> +
>  static void create_tag(const struct object_id *object, const char *object_ref,
>                        const char *tag,
>                        struct strbuf *buf, struct create_tag_options *opt,
> @@ -251,7 +288,7 @@ static void create_tag(const struct object_id *object, const char *object_ref,
>  {
>         enum object_type type;
>         struct strbuf header = STRBUF_INIT;
> -       char *path = NULL;
> +       char *path = git_pathdup("TAG_EDITMSG");
>
>         type = oid_object_info(the_repository, object, NULL);
>         if (type <= OBJ_NONE)
> @@ -271,31 +308,7 @@ static void create_tag(const struct object_id *object, const char *object_ref,
>                     git_committer_info(IDENT_STRICT));
>
>         if (!opt->message_given || opt->use_editor) {
> -               int fd;
> -
> -               /* write the template message before editing: */
> -               path = git_pathdup("TAG_EDITMSG");
> -               fd = open(path, O_CREAT | O_TRUNC | O_WRONLY, 0600);
> -               if (fd < 0)
> -                       die_errno(_("could not create file '%s'"), path);
> -
> -               if (opt->message_given) {
> -                       write_or_die(fd, buf->buf, buf->len);
> -                       strbuf_reset(buf);
> -               } else if (!is_null_oid(prev)) {
> -                       write_tag_body(fd, prev);
> -               } else {
> -                       struct strbuf buf = STRBUF_INIT;
> -                       strbuf_addch(&buf, '\n');
> -                       if (opt->cleanup_mode == CLEANUP_ALL)
> -                               strbuf_commented_addf(&buf, _(tag_template), tag, comment_line_char);
> -                       else
> -                               strbuf_commented_addf(&buf, _(tag_template_nocleanup), tag, comment_line_char);
> -                       write_or_die(fd, buf.buf, buf.len);
> -                       strbuf_release(&buf);
> -               }
> -               close(fd);
> -
> +               prepare_tag_template(buf, opt, prev, path, tag);
>                 if (launch_editor(path, buf, NULL)) {
>                         fprintf(stderr,
>                         _("Please supply the message using either -m or -F option.\n"));
> --
> 2.23.0
>