Re: [PATCH v2 15/19] pull: teach git pull about --rebase

> +/**
> + * Returns remote's upstream branch for the current branch. If remote is NULL,
> + * the current branch's configured default remote is used. Returns NULL if
> + * `remote` does not name a valid remote, HEAD does not point to a branch,
> + * remote is not the branch's configured remote or the branch does not have any
> + * configured upstream branch.
> + */
> +static char *get_upstream_branch(const char *remote)
> +{
> +	struct remote *rm;
> +	struct branch *curr_branch;
> +
> +	rm = remote_get(remote);
> +	if (!rm)
> +		return NULL;
> +
> +	curr_branch = branch_get("HEAD");
> +	if (!curr_branch)
> +		return NULL;
> +
> +	if (curr_branch->remote != rm)
> +		return NULL;
> +
> +	if (!curr_branch->merge_nr)
> +		return NULL;
> +
> +	return xstrdup(curr_branch->merge[0]->dst);
> +}