Use correct min/max htlc in test util for constructing blinded pay params.

In testing, we use channel updates to construct blinded paths and the
{Forward,Receive}Tlvs encoded within. Given a blinded path from node A > B > C,
we currently use channel_update_A->B to construct the payment constraints for
A’s blinded payload.

This is incorrect for setting A's PaymentConstraints::htlc_minimum_msat,
because channel_update_A->B contains the minimum value that *B* will accept,
and we want the constraints to contain the min value that *A* will accept.

This never caused test failures before because min/max htlc values were always
identical in both channel directions.

Therefore, set A’s htlc min/max values to the min/max that A will accept.

diff --git a/lightning/src/ln/blinded_payment_tests.rs b/lightning/src/ln/blinded_payment_tests.rs
index 816e0170704f4483de775d8cdd83ec475d722a2f..2a93cadd7fdbbe1a68a290f655b031dee9df712c 100644 (file)
--- a/lightning/src/ln/blinded_payment_tests.rs
+++ b/lightning/src/ln/blinded_payment_tests.rs
@@ -33,7 +33,9 @@ fn blinded_payment_path(
        keys_manager: &test_utils::TestKeysInterface
 ) -> (BlindedPayInfo, BlindedPath) {
        let mut intermediate_nodes = Vec::new();
-       for (node_id, chan_upd) in node_ids.iter().zip(channel_upds) {
+       let mut intro_node_min_htlc_opt = Some(intro_node_min_htlc);
+       let mut intro_node_max_htlc_opt = Some(intro_node_max_htlc);
+       for (idx, (node_id, chan_upd)) in node_ids.iter().zip(channel_upds).enumerate() {
                intermediate_nodes.push(ForwardNode {
                        node_id: *node_id,
                        tlvs: ForwardTlvs {
@@ -45,24 +47,28 @@ fn blinded_payment_path(
                                },
                                payment_constraints: PaymentConstraints {
                                        max_cltv_expiry: u32::max_value(),
-                                       htlc_minimum_msat: chan_upd.htlc_minimum_msat,
+                                       htlc_minimum_msat: intro_node_min_htlc_opt.take()
+                                               .unwrap_or_else(|| channel_upds[idx - 1].htlc_minimum_msat),
                                },
                                features: BlindedHopFeatures::empty(),
                        },
-                       htlc_maximum_msat: chan_upd.htlc_maximum_msat,
+                       htlc_maximum_msat: intro_node_max_htlc_opt.take()
+                               .unwrap_or_else(|| channel_upds[idx - 1].htlc_maximum_msat),
                });
        }
        let payee_tlvs = ReceiveTlvs {
                payment_secret,
                payment_constraints: PaymentConstraints {
                        max_cltv_expiry: u32::max_value(),
-                       htlc_minimum_msat: channel_upds.last().unwrap().htlc_minimum_msat,
+                       htlc_minimum_msat:
+                               intro_node_min_htlc_opt.unwrap_or_else(|| channel_upds.last().unwrap().htlc_minimum_msat),
                },
        };
        let mut secp_ctx = Secp256k1::new();
        BlindedPath::new_for_payment(
                &intermediate_nodes[..], *node_ids.last().unwrap(), payee_tlvs,
-               channel_upds.last().unwrap().htlc_maximum_msat, TEST_FINAL_CLTV as u16, keys_manager, &secp_ctx
+               intro_node_max_htlc_opt.unwrap_or_else(|| channel_upds.last().unwrap().htlc_maximum_msat),
+               TEST_FINAL_CLTV as u16, keys_manager, &secp_ctx
        ).unwrap()
 }