Re: [PATCH] submodule--helper: set alternateLocation for cloned submodules

[Stefan Beller <sbeller@google.com>]

On Wed, Dec 7, 2016 at 10:42 AM,  <vi0oss@gmail.com> wrote:
> From: Vitaly _Vi Shukela <vi0oss@gmail.com>

Thanks for contributing to Git!
(/me looks up if you have sent patches already as you
seem to know how to do that. :) unrelated side note: Maybe you want
to send a patch for the .mailmap file mapping your two email addresses
together, c.f. "git log -- .mailmap")

>
> Git v2.11 introduced "git clone --recursive --referece ...",
> but it didn't put the alternates for _nested_ submodules.

This message is targeted at people familiar with gits code base,
so we can be more specific. e.g.

    In 31224cbdc7 (clone: recursive and reference option triggers
    submodule alternates, 2016-08-17) a mechanism was added to
    have submodules referenced.  It did not address _nested_
    submodules, however.

>
> This patch makes all not just the root repository, but also
> all submodules (recursively) have submodule.alternateLocation
> and submodule.alternateErrorStrategy configured, making Git
> search for possible alternates for nested submodules as well.

Sounds great!

>
> As submodule's alternate target does not end in .git/objects
> (rather .git/modules/qqqqqq/objects), this alternate target
> path restriction for in add_possible_reference_from_superproject
> relates from "*.git/objects" to just */objects".

I wonder if this check is too weak and we actually have to check for
either .git/objects or modules/<name/possibly/having/slashes>/objects.
When writing the referenced commit I assumed we'd need a stronger check
to be safer and not add some random location as a possible alternate.

>
> New tests have been added to t7408-submodule-reference.

Thanks!

>
> Signed-off-by: Vitaly _Vi Shukela <vi0oss@gmail.com>
> ---
>  builtin/submodule--helper.c    | 24 ++++++++++++--
>  t/t7408-submodule-reference.sh | 73 ++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 95 insertions(+), 2 deletions(-)
>
> diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
> index 4beeda5..93dae62 100644
> --- a/builtin/submodule--helper.c
> +++ b/builtin/submodule--helper.c
> @@ -498,9 +498,9 @@ static int add_possible_reference_from_superproject(
>
>         /*
>          * If the alternate object store is another repository, try the
> -        * standard layout with .git/modules/<name>/objects
> +        * standard layout with .git/(modules/<name>)+/objects
>          */
> -       if (ends_with(alt->path, ".git/objects")) {
> +       if (ends_with(alt->path, "/objects")) {
>                 char *sm_alternate;
>                 struct strbuf sb = STRBUF_INIT;
>                 struct strbuf err = STRBUF_INIT;
> @@ -672,6 +672,26 @@ static int module_clone(int argc, const char **argv, const char *prefix)
>                 die(_("could not get submodule directory for '%s'"), path);
>         git_config_set_in_file(p, "core.worktree",
>                                relative_path(path, sm_gitdir, &rel_path));
> +
> +       /* setup alternateLocation and alternateErrorStrategy in the cloned submodule if needed */
> +       {

Usually we do not use braces to further nest code, please remove this nesting.

> +               char *sm_alternate = NULL, *error_strategy = NULL;
> +
> +               git_config_get_string("submodule.alternateLocation", &sm_alternate);
> +               if (sm_alternate) {
> +                       git_config_set_in_file(p, "submodule.alternateLocation",
> +                                                  sm_alternate);
> +               }
> +               git_config_get_string("submodule.alternateErrorStrategy", &error_strategy);
> +               if (error_strategy) {
> +                       git_config_set_in_file(p, "submodule.alternateErrorStrategy",
> +                                                  error_strategy);
> +               }
> +
> +               free(sm_alternate);
> +               free(error_strategy);
> +       }
> +
>         strbuf_release(&sb);
>         strbuf_release(&rel_path);
>         free(sm_gitdir);
> diff --git a/t/t7408-submodule-reference.sh b/t/t7408-submodule-reference.sh
> index 1c1e289..7b64725 100755
> --- a/t/t7408-submodule-reference.sh
> +++ b/t/t7408-submodule-reference.sh
> @@ -125,4 +125,77 @@ test_expect_success 'ignoring missing submodule alternates passes clone and subm
>         )
>  '
>
> +test_expect_success 'preparing second superproject with a nested submodule' '
> +       test_create_repo supersuper &&
> +       (
> +               cd supersuper &&
> +               echo I am super super. >file &&

Usually we quote strings containing white space, e.g. echo "I am ..." >actual

> +               git add file &&
> +               git commit -m B-super-super-initial
> +               git submodule add "file://$base_dir/super" subwithsub &&
> +               git commit -m B-super-super-added &&
> +               git submodule update --init --recursive &&
> +               git repack -ad
> +       ) &&
> +       echo not cleaning supersuper

This echo is left in for debugging purposes?