Re: [PATCH 2/2] submodule: Try harder to fetch needed sha1 by direct fetching sha1

From: Stefan Beller <sbeller@google.com>
Date: Feb 23, 2016, 00:28 UTC
Message-ID: <CAGZ79ka-iAHvopwp==fTiuL13sJ_KzqotCNoOgQLJzvpNGH2HA@mail.gmail.com>
In-Reply-To: <xmqqzius2t31.fsf@gitster.mtv.corp.google.com>

On Mon, Feb 22, 2016 at 4:01 PM, Junio C Hamano <gitster@pobox.com> wrote:

Show 17 quoted lines

>
> Stefan Beller <sbeller@google.com> writes:
>
> > We may want to discuss the error message. It is the same as in the case
> > before (git-fetch <no args>), this is good for translation, but may be bad
> > for the user as we may want to give extra information.
> > ("We fetched for you and it worked, however the sha1 was not included,
> > so we fetched again the server broke it, so we error out.  You used to
> > see error message: ....")
> >
> > Although this may be too much information?
>
> Now the "go to that submodule directory and see if $sha1 is
> reachable from any of the ref" check is written twice exactly the
> same way, it deserves to become a small helper function, I think.
>
> Perhaps something along this line?

This looks very readable.

Feel free to drop both my patches and just introduce this patch as yours!

Show 17 quoted lines

>
>  git-submodule.sh | 29 ++++++++++++++++++++++++++---
>  1 file changed, 26 insertions(+), 3 deletions(-)
>
> diff --git a/git-submodule.sh b/git-submodule.sh
> index 9bc5c5f..836348f 100755
> --- a/git-submodule.sh
> +++ b/git-submodule.sh
> @@ -591,6 +591,24 @@ cmd_deinit()
>         done
>  }
>
> +is_tip_reachable () (
> +       clear_local_git_env
> +       cd "$1" &&
> +       rev=$(git rev-list -n 1 "$2" --not --all 2>/dev/null) &&
> +       test -z "$rev"

While we're talking about this code anyway, I wondered if we can make it more cryptic again (just kidding!) and shorten it a bit by using the

    is_tip_reachable () (
        clear_local_git_env
        test -z $(git -C $1 rev-list -n 1 "$2" --not --all 2>/dev/null)
    )

Show 31 quoted lines

> +)
> +
> +fetch_in_submodule () (
> +       clear_local_git_env
> +       cd "$1" &&
> +       case "$2" in
> +       '')
> +               git fetch ;;
> +       *)
> +               git fetch $(get_default_remote) "$2" ;;
> +       esac
> +)
> +
>  #
>  # Update each submodule path to correct revision, using clone and checkout as needed
>  #
> @@ -745,9 +763,14 @@ Maybe you want to use 'update --init'?")"
>                         then
>                                 # Run fetch only if $sha1 isn't present or it
>                                 # is not reachable from a ref.
> -                               (clear_local_git_env; cd "$sm_path" &&
> -                                       ( (rev=$(git rev-list -n 1 $sha1 --not --all 2>/dev/null) &&
> -                                        test -z "$rev") || git-fetch)) ||
> +                               is_tip_reachable "$sm_path" "$sha1" ||
> +                               fetch_in_submodule "$sm_path" ||
> +                               die "$(eval_gettext "Unable to fetch in submodule path '\$displaypath'")"
> +
> +                               # Now we tried the usual fetch, but $sha1 may
> +                               # not be reachable from any of the refs
> +                               is_tip_reachable "$sm_path" "$sha1" ||
> +                               fetch_in_submodule "$sm_path" "$sha1" ||

For another split second I wondered about the return code of is_tip_reachable, if the result is actually negated, but reading the chaining here, makes sense.

Thanks, Stefan

>                                 die "$(eval_gettext "Unable to fetch in submodule path '\$displaypath'")"
>                         fi
>