Re: [PATCH 2/4] revision: add rev_input_given flag

> Normally a caller that invokes setup_revisions() has to
> check rev.pending to see if anything was actually queued for
> the traversal. But they can't tell the difference between
> two cases:
>
>   1. The user gave us no tip from which to start a
>      traversal.
>
>   2. The user tried to give us tips via --glob, --all, etc,
>      but their patterns ended up being empty.
>
> Let's set a flag in the rev_info struct that callers can use
> to tell the difference.  We can set this from the
> init_all_refs_cb() function.  That's a little funny because
> it's not exactly about initializing the "cb" struct itself.
> But that function is the common setup place for doing
> pattern traversals that is used by --glob, --all, etc.

> Signed-off-by: Jeff King <peff@peff.net>
> ---
>  revision.c | 1 +
>  revision.h | 7 +++++++
>  2 files changed, 8 insertions(+)
>
> diff --git a/revision.c b/revision.c
> index 6603af944..08d5806b8 100644
> --- a/revision.c
> +++ b/revision.c
> @@ -1168,6 +1168,7 @@ static void init_all_refs_cb(struct all_refs_cb *cb, struct rev_info *revs,
>  {
>  	cb->all_revs = revs;
>  	cb->all_flags = flags;
> +	revs->rev_input_given = 1;
>  }
>  
>  void clear_ref_exclusion(struct string_list **ref_excludes_p)
> diff --git a/revision.h b/revision.h
> index f96e7f7f4..c8f4e91f2 100644
> --- a/revision.h
> +++ b/revision.h
> @@ -71,6 +71,13 @@ struct rev_info {
>  	const char *def;
>  	struct pathspec prune_data;
>  
> +	/*
> +	 * Whether the arguments parsed by setup_revisions() included any
> +	 * "input" revisions that might still have yielded an empty pending
> +	 * list (e.g., patterns like "--all" or "--glob").
> +	 */
> +	int rev_input_given;
> +
>  	/* topo-sort */
>  	enum rev_sort_order sort_order;