Re: [PATCH v3 4/4] submodule: port submodule subcommand 'summary' from shell to C

> On Mon, 2020-08-24 at 14:16 +0530, Shourya Shukla wrote:
> > Or rather, we can do this:
> > 
> > -----8<-----
> > if (S_ISGITLINK(p->mod_src)) {
> > 		struct strbuf sb = STRBUF_INIT;
> > 		strbuf_addstr(&sb, p->sm_path);
> > 		if (is_nonbare_repository_dir(&sb))
> > 			src_abbrev = verify_submodule_committish(p->sm_path,
> > 								                     oid_to_hex(&p->oid_src));
> > 		strbuf_release(&sb);
> > 		if (!src_abbrev) {
> > 			missing_src = 1;
> > 			/*
> > 			 * As `rev-parse` failed, we fallback to getting
> > 			 * the abbreviated hash using oid_src. We do
> > 			 * this as we might still need the abbreviated
> > 			 * hash in cases like a submodule type change, etc.
> > 			 */
> > 			src_abbrev = xstrndup(oid_to_hex(&p->oid_src), 7);
> > 		}
> > 	} else {
> > 		/*
> > 		 * The source does not point to a submodule.
> > 		 * So, we fallback to getting the abbreviation using
> > 		 * oid_src as we might still need the abbreviated
> > 		 * hash in cases like submodule add, etc.
> > 		 */
> > 		src_abbrev = xstrndup(oid_to_hex(&p->oid_src), 7);
> > 	}
> > ----->8-----
> > 
> > Similarly for dst as well. This solution passes all the tests and does
> > not call 'verify_submodule_committish()' all the time. The previous
> > approach failed a couple of tests, this one seems fine to me.
> > 
> > How is this one?
> > 
> 
> This is more or less what I had in mind initially. But later after
> being reminded about the fact that there's a code path which calls
> `generate_submodule_summary` only when `is_nonbare_repository_dir`
> succeeds, I realized any conditional that uses
> `is_nonbare_repository_dir` or the likes of it would be confusing. So,
> I think a better approach would be something like:

> -- 8< --
> diff --git builtin/submodule--helper.c builtin/submodule--helper.c
> index 63ea39025d..b490108cd9 100644
> --- builtin/submodule--helper.c
> +++ builtin/submodule--helper.c
> @@ -1036,7 +1036,7 @@ static void print_submodule_summary(struct summary_cb *info, char* errmsg,
>  static void generate_submodule_summary(struct summary_cb *info,
>                                        struct module_cb *p)
>  {
> -       char *displaypath, *src_abbrev, *dst_abbrev;
> +       char *displaypath, *src_abbrev = NULL, *dst_abbrev;
>         int missing_src = 0, missing_dst = 0;
>         char *errmsg = NULL;
>         int total_commits = -1;
> @@ -1062,8 +1062,9 @@ static void generate_submodule_summary(struct summary_cb *info,
>         }
>  
>         if (S_ISGITLINK(p->mod_src)) {
> -               src_abbrev = verify_submodule_committish(p->sm_path,
> -                                                        oid_to_hex(&p->oid_src));
> +               if (p->status != 'D')
> +                       src_abbrev = verify_submodule_committish(p->sm_path,
> +                                                                oid_to_hex(&p->oid_src));
>                 if (!src_abbrev) {
>                         missing_src = 1;
>                         /*
> diff --git t/t7421-submodule-summary-add.sh t/t7421-submodule-summary-add.sh
> index 59a9b00467..b070f13714 100755
> --- t/t7421-submodule-summary-add.sh
> +++ t/t7421-submodule-summary-add.sh
> @@ -58,7 +58,7 @@ test_expect_success 'submodule summary output for submodules with changed paths'
>         git commit -m "change submodule path" &&
>         rev=$(git -C sm rev-parse --short HEAD^) &&
>         git submodule summary HEAD^^ -- my-subm >actual 2>err &&
> -       grep "fatal:.*my-subm" err &&
> +       test_must_be_empty err &&
>         cat >expected <<-EOF &&
>         * my-subm ${rev}...0000000:
>  
> -- >8 --
> 
> I suggest this as the other code path that calls
> `generate_submodule_summary` without going through the
> `is_nonbare_repository_dir` condition is the one where we get
> `p->status` as 'T' (typechange) or 'D' (deleted). We don't have to
> worry about 'T' as we would want the hash for the new object anyway.
> That leaves us with 'D' which we indeed have to handle.