Function direct_pay_override

plugins/libplugin-pay.c:3465–3510

			  shadow_route_init, shadow_route_cb);

static struct command_result *direct_pay_override(struct payment *p)
{
	/* The root has performed the search for a direct channel. */
	struct payment *root = payment_root(p);
	struct direct_pay_data *d;
	struct channel_hint *hint = NULL;

	/* If we were unable to find a direct channel we don't need to do
	 * anything. */
	d = payment_mod_directpay_get_data(root);

	if (d->chan == NULL)
		return payment_continue(p);

	/* If we have a channel we need to make sure that it still has
	 * sufficient capacity. Look it up in the channel_hints. */
	hint = channel_hint_set_find(root->hints, d->chan);
	if (hint && hint->enabled &&
	    amount_msat_greater(hint->estimated_capacity, p->our_amount)) {
		if (p->getroute->cltv > p->constraints.cltv_budget) {
			paymod_log(p, LOG_DBG,
				   "Direct channel (%s) skipped: "
				   "CLTV delay %u exceeds budget %u.",
				   fmt_short_channel_id_dir(tmpctx, &hint->scid),
				   p->getroute->cltv, p->constraints.cltv_budget);
			return payment_continue(p);
		}

		/* Now build a route that consists only of this single hop */
		p->route = tal_arr(p, struct route_hop, 1);
		p->route[0].amount = p->our_amount;
		p->route[0].delay = p->getroute->cltv;
		p->route[0].scid = hint->scid.scid;
		p->route[0].direction = hint->scid.dir;
		p->route[0].node_id = *p->route_destination;
		p->route[0].capacity = hint->capacity;
		paymod_log(p, LOG_DBG,
			   "Found a direct channel (%s) with sufficient "
			   "capacity, skipping route computation.",
			   fmt_short_channel_id_dir(tmpctx, &hint->scid));

		payment_set_step(p, PAYMENT_STEP_GOT_ROUTE);
	}

	return payment_continue(p);
}

/* Now that we have the listpeerchannels result for the root payment, let's search
 * for a direct channel that is a) connected and b) in state normal. We will