From fe1ee22f42d1912970485c5fa670dec600094a60 Mon Sep 17 00:00:00 2001
From: Carsten Otto <git@c-otto.de>
Date: Mon, 15 Jan 2024 09:38:14 +0100
Subject: [PATCH] wait for 100th attempt to succeed

---
 .../pickhardtpayments/PaymentLoop.java        | 16 +++++++++------
 .../pickhardtpayments/PaymentLoopTest.java    | 20 +++++++++++++++++++
 2 files changed, 30 insertions(+), 6 deletions(-)

diff --git a/pickhardt-payments/src/main/java/de/cotto/lndmanagej/pickhardtpayments/PaymentLoop.java b/pickhardt-payments/src/main/java/de/cotto/lndmanagej/pickhardtpayments/PaymentLoop.java
index 42b56ad2..c22c3054 100644
--- a/pickhardt-payments/src/main/java/de/cotto/lndmanagej/pickhardtpayments/PaymentLoop.java
+++ b/pickhardt-payments/src/main/java/de/cotto/lndmanagej/pickhardtpayments/PaymentLoop.java
@@ -99,13 +99,17 @@ public Instance(
         private void start() {
             int loopIterationCounter = 0;
             int failureCounter = 0;
-            while (shouldContinue(loopIterationCounter)) {
+            while (shouldContinue()) {
                 loopIterationCounter++;
                 Coins residualAmount = totalAmountToSend.subtract(inFlight);
                 if (Coins.NONE.equals(residualAmount)) {
                     paymentStatus.info(TIMEOUT_MESSAGE);
                     return;
                 }
+                if (shouldAbort(loopIterationCounter)) {
+                    paymentStatus.failed("Failing after " + MAX_NUMBER_OF_LOOPS + " loop iterations.");
+                    return;
+                }
                 addLoopIterationInfo(loopIterationCounter, residualAmount);
                 MultiPathPayment multiPathPayment = multiPathPaymentSplitter.getMultiPathPaymentTo(
                         destination,
@@ -166,11 +170,7 @@ private void addLoopIterationInfo(int loopCounter, Coins residualAmount) {
             );
         }
 
-        private boolean shouldContinue(int loopIterationCounter) {
-            if (loopIterationCounter >= MAX_NUMBER_OF_LOOPS) {
-                paymentStatus.failed("Failing after " + MAX_NUMBER_OF_LOOPS + " loop iterations.");
-                return false;
-            }
+        private boolean shouldContinue() {
             updateInformation();
             if (!paymentStatus.isPending()) {
                 return false;
@@ -183,6 +183,10 @@ private boolean shouldContinue(int loopIterationCounter) {
             return paymentStatus.isPending();
         }
 
+        private boolean shouldAbort(int loopIterationCounter) {
+            return paymentStatus.isPending() && loopIterationCounter > MAX_NUMBER_OF_LOOPS;
+        }
+
         private void updateInformation() {
             inFlight = multiPathPaymentObserver.getInFlight(paymentHash);
             if (multiPathPaymentObserver.isSettled(paymentHash)) {
diff --git a/pickhardt-payments/src/test/java/de/cotto/lndmanagej/pickhardtpayments/PaymentLoopTest.java b/pickhardt-payments/src/test/java/de/cotto/lndmanagej/pickhardtpayments/PaymentLoopTest.java
index 8ffaf942..bf6949c8 100644
--- a/pickhardt-payments/src/test/java/de/cotto/lndmanagej/pickhardtpayments/PaymentLoopTest.java
+++ b/pickhardt-payments/src/test/java/de/cotto/lndmanagej/pickhardtpayments/PaymentLoopTest.java
@@ -20,6 +20,7 @@
 import org.mockito.InjectMocks;
 import org.mockito.Mock;
 import org.mockito.junit.jupiter.MockitoExtension;
+import org.mockito.stubbing.OngoingStubbing;
 
 import java.util.LinkedHashMap;
 import java.util.Map;
@@ -124,6 +125,25 @@ void fails_after_one_hundred_loop_iterations() {
         verify(grpcSendToRoute).forceFailureForPayment(DECODED_PAYMENT_REQUEST);
     }
 
+    @Test
+    void waits_for_last_iteration_to_succeed() {
+        when(multiPathPaymentSplitter.getMultiPathPaymentTo(any(), any(), any(), anyInt()))
+                .thenReturn(MULTI_PATH_PAYMENT);
+        OngoingStubbing<Boolean> stubbing = when(multiPathPaymentObserver.isSettled(PAYMENT_HASH));
+        for (int i = 0; i < 100; i++) {
+            stubbing = stubbing.thenReturn(false);
+        }
+        stubbing.thenReturn(true);
+        paymentLoop.start(DECODED_PAYMENT_REQUEST, PAYMENT_OPTIONS, paymentStatus);
+
+        SoftAssertions softly = new SoftAssertions();
+        softly.assertThat(paymentStatus.isSuccess()).isTrue();
+        softly.assertThat(readAll(paymentStatus)).map(InstantWithString::string)
+                .doesNotContain("Failing after 100 loop iterations.");
+        softly.assertAll();
+        verify(multiPathPaymentSplitter, times(100)).getMultiPathPaymentTo(any(), any(), any(), anyInt());
+    }
+
     @Test
     void cancels_invoice_from_own_node() {
         when(grpcGetInfo.getPubkey()).thenReturn(DECODED_PAYMENT_REQUEST.destination());