fix: when paying, also consider "expensive" hops from own node

if "ignore fees from own channels" is not set, local channels should be considered no matter the fee rate
C-Otto · May 4, 2024 · 051c7bf · 051c7bf
1 parent 1dbb355
commit 051c7bf
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Showing 2 changed files with 31 additions and 2 deletions.
diff --git a/pickhardt-payments/src/main/java/de/cotto/lndmanagej/pickhardtpayments/EdgeComputation.java b/pickhardt-payments/src/main/java/de/cotto/lndmanagej/pickhardtpayments/EdgeComputation.java
@@ -132,7 +132,9 @@ private boolean shouldIgnore(
             return false;
         }
         long feeRate = policy.feeRate();
-        if (feeRate >= feeRateLimit) {
+        boolean hopIsRelevantForFeeCheck =
+                !pubkey.equals(channelEdge.source()) || !paymentOptions.ignoreFeesForOwnChannels();
+        if (feeRate >= feeRateLimit && hopIsRelevantForFeeCheck) {
             return true;
         }
         if (isEdgeToUnwantedFirstHop(channelEdge, paymentOptions, pubkey)) {

diff --git a/...rdt-payments/src/test/java/de/cotto/lndmanagej/pickhardtpayments/EdgeComputationTest.java b/...rdt-payments/src/test/java/de/cotto/lndmanagej/pickhardtpayments/EdgeComputationTest.java
@@ -151,6 +151,33 @@ void does_not_add_edge_with_fee_rate_at_or_above_limit() {
         ).containsExactly(CHANNEL_ID_3);
     }
 
+    @Test
+    void adds_edge_with_fee_rate_at_limit_if_first_hop_and_fee_is_ignored() {
+        int feeRateLimit = 1000;
+        PaymentOptions paymentOptions = PaymentOptions.forFeeRateLimit(feeRateLimit);
+        DirectedChannelEdge edge =
+                new DirectedChannelEdge(CHANNEL_ID, CAPACITY, PUBKEY_4, PUBKEY_2, policy(feeRateLimit), Policy.UNKNOWN);
+        when(grpcGraph.getChannelEdges()).thenReturn(Optional.of(Set.of(edge)));
+        assertThat(edgeComputation.getEdges(paymentOptions, MAX_TIME_LOCK_DELTA).edges()).isNotEmpty();
+    }
+
+    @Test
+    void does_not_add_edge_with_fee_rate_at_limit_if_first_hop_and_fee_is_not_ignored() {
+        long feeRateLimit = 2000L;
+        PaymentOptions paymentOptions = new PaymentOptions(
+                Optional.of(0),
+                Optional.of(feeRateLimit),
+                Optional.empty(),
+                false,
+                Optional.empty(),
+                Optional.empty()
+        );
+        DirectedChannelEdge edge =
+                new DirectedChannelEdge(CHANNEL_ID, CAPACITY, PUBKEY_4, PUBKEY, policy(feeRateLimit), Policy.UNKNOWN);
+        when(grpcGraph.getChannelEdges()).thenReturn(Optional.of(Set.of(edge)));
+        assertThat(edgeComputation.getEdges(paymentOptions, MAX_TIME_LOCK_DELTA).edges()).isEmpty();
+    }
+
     @Test
     void does_not_add_first_hop_edge_with_fee_rate_at_or_above_limit_for_first_hops() {
         Pubkey ownPubkey = EDGE.startNode();
@@ -482,7 +509,7 @@ private void mockEdge() {
         when(grpcGraph.getChannelEdges()).thenReturn(Optional.of(Set.of(edge)));
     }
 
-    private static Policy policy(int feeRate) {
+    private static Policy policy(long feeRate) {
         return new Policy(feeRate, Coins.NONE, true, 40, Coins.NONE, Coins.NONE);
     }