RE: [PATCH v3 25/32] diff-merges: let new options enable diff without -p

> diff --git a/log-tree.c b/log-tree.c
> index f9385b1dae6f..9f50a81e537e 100644
> --- a/log-tree.c
> +++ b/log-tree.c
> @@ -899,15 +899,21 @@ static int log_tree_diff(struct rev_info *opt, struct commit *commit, struct log
>  	int showed_log;
>  	struct commit_list *parents;
>  	struct object_id *oid;
> +	int is_merge;
> +	int all_need_diff = opt->diff || opt->diffopt.flags.exit_with_status;
>  
> -	if (!opt->diff && !opt->diffopt.flags.exit_with_status)
> +	if (!all_need_diff && !opt->merges_need_diff)
>  		return 0;
>  
>  	parse_commit_or_die(commit);
>  	oid = get_commit_tree_oid(commit);
>  
> -	/* Root commit? */
>  	parents = get_saved_parents(opt, commit);
> +	is_merge = parents && parents->next;
> +	if (!is_merge && !all_need_diff)
> +		return 0;
> +
> +	/* Root commit? */
>  	if (!parents) {
>  		if (opt->show_root_diff) {
>  			diff_root_tree_oid(oid, "", &opt->diffopt);