Re: [PATCH] Dereference tag repeatedly until we get a non-tag.

[Jon Seymour <jon.seymour@gmail.com>]

This seems reasonable to me. I have thought this would be useful on
several occasions and haven't yet conceived of a counterexample where
it would break something.

On 7/11/05, Junio C Hamano <junkio@cox.net> wrote:
> When we allow a tag object in place of a commit object, we only
> dereferenced the given tag once, which causes a tag that points
> at a tag that points at a commit to be rejected.  Instead,
> dereference tag repeatedly until we get a non-tag.
> 
> This patch makes change to two functions:
> 
>  - commit.c::lookup_commit_reference() is used by merge-base,
>    rev-tree and rev-parse to convert user supplied SHA1 to that of
>    a commit.
>  - rev-list uses its own get_commit_reference() to do the same.
> 
> Dereferencing tags this way helps both of these uses.
> 
> Signed-off-by: Junio C Hamano <junkio@cox.net>
> ---
> 
> *** Whether having a tag pointing at another tag is a separate
> *** issue, but I do not see a reason to forbid it.  Maybe it
> *** is used to represent a chain of trust.
> 
>  commit.c   |    5 +++--
>  rev-list.c |    4 ++--
>  2 files changed, 5 insertions(+), 4 deletions(-)
> 
> 0dc9377363ee73c5e3f3711d6f82e49886ce8c6a
> diff --git a/commit.c b/commit.c
> --- a/commit.c
> +++ b/commit.c
> @@ -52,8 +52,9 @@ struct commit *lookup_commit_reference(c
> 
>         if (!obj)
>                 return NULL;
> -       if (obj->type == tag_type)
> -               obj = ((struct tag *)obj)->tagged;
> +       while (obj->type == tag_type)
> +               obj = parse_object(((struct tag *)obj)->tagged->sha1);
> +
>         return check_commit(obj, sha1);
>  }
> 
> diff --git a/rev-list.c b/rev-list.c
> --- a/rev-list.c
> +++ b/rev-list.c
> @@ -367,12 +367,12 @@ static struct commit *get_commit_referen
>         /*
>          * Tag object? Look what it points to..
>          */
> -       if (object->type == tag_type) {
> +       while (object->type == tag_type) {
>                 struct tag *tag = (struct tag *) object;
>                 object->flags |= flags;
>                 if (tag_objects && !(object->flags & UNINTERESTING))
>                         add_pending_object(object, tag->tag);
> -               object = tag->tagged;
> +               object = parse_object(tag->tagged->sha1);
>         }
> 
>         /*
> 
> -
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-- 
homepage: http://www.zeta.org.au/~jon/
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