Fix off-by-one retry count when using exponential backoff

implementation/src/main/java/io/smallrye/mutiny/helpers/ExponentialBackoff.java

@@ -39,7 +39,7 @@ public static Function<Multi<Throwable>, Publisher<Long>> randomExponentialBacko
         AtomicInteger index = new AtomicInteger();
         return t -> t
                 .onItem().transformToUni(failure -> {
-                    int iteration = index.incrementAndGet();
+                    int iteration = index.getAndIncrement();
                     if (iteration >= numRetries) {
                         return Uni.createFrom().failure(
                                 new IllegalStateException("Retries exhausted: " + iteration + "/" + numRetries,

implementation/src/test/java/io/smallrye/mutiny/operators/MultiOnFailureRetryWhenTest.java

@@ -11,7 +11,6 @@
 import java.util.concurrent.atomic.AtomicInteger;
 
 import org.junit.jupiter.api.BeforeEach;
-import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 import io.smallrye.mutiny.Multi;
@@ -87,7 +86,6 @@ public void testWithOtherStreamFailing() {
     }
 
     @Test
-    @Disabled("To be investigated - the switch to the strict serializer broken the cancellation check")
     public void testWhatTheWhenStreamFailsTheUpstreamIsCancelled() {
         AtomicBoolean subscribed = new AtomicBoolean();
         AtomicBoolean cancelled = new AtomicBoolean();
@@ -318,9 +316,9 @@ public void testRetryWithRandomBackoff() {
                 .onFailure().retry().withBackOff(Duration.ofMillis(10), Duration.ofHours(1)).withJitter(0.1)
                 .atMost(4)
                 .subscribe().withSubscriber(AssertSubscriber.create(100));
-        await().until(() -> subscriber.getItems().size() >= 8);
+        await().until(() -> subscriber.getItems().size() >= 10);
         subscriber
-                .assertItems(0, 1, 0, 1, 0, 1, 0, 1)
+                .assertItems(0, 1, 0, 1, 0, 1, 0, 1, 0, 1) // Initial subscription + 4 retries
                 .assertFailedWith(IllegalStateException.class, "Retries exhausted");
 
     }
@@ -335,9 +333,9 @@ public void testRetryWithRandomBackoffAndDefaultJitter() {
                 .atMost(4)
                 .subscribe().withSubscriber(AssertSubscriber.create(100));
 
-        await().until(() -> subscriber.getItems().size() >= 8);
+        await().until(() -> subscriber.getItems().size() >= 10);
         subscriber
-                .assertItems(0, 1, 0, 1, 0, 1, 0, 1)
+                .assertItems(0, 1, 0, 1, 0, 1, 0, 1, 0, 1) // Initial subscription + 4 retries
                 .assertFailedWith(IllegalStateException.class, "Retries exhausted: 4/4");
     }
 
@@ -352,9 +350,9 @@ public void testRetryWithDefaultMax() {
 
         await()
                 .atMost(1, TimeUnit.MINUTES)
-                .until(() -> subscriber.getItems().size() >= 8);
+                .until(() -> subscriber.getItems().size() >= 10);
         subscriber
-                .assertItems(0, 1, 0, 1, 0, 1, 0, 1)
+                .assertItems(0, 1, 0, 1, 0, 1, 0, 1, 0, 1) // Initial subscription + 4 retries
                 .assertFailedWith(IllegalStateException.class, "Retries exhausted: 4/4");
     }
 

implementation/src/test/java/io/smallrye/mutiny/operators/UniOnFailureRetryTest.java

@@ -1,5 +1,6 @@
 package io.smallrye.mutiny.operators;
 
+import static org.assertj.core.api.Assertions.assertThat;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 
 import java.util.concurrent.atomic.AtomicInteger;
@@ -84,4 +85,19 @@ public void testWithMapperFailure() {
                 .subscribe().withSubscriber(UniAssertSubscriber.create())
                 .assertItem(1);
     }
+
+    @Test
+    public void testThatNumberOfRetryIfCorrect() {
+        AtomicInteger calls = new AtomicInteger();
+
+        UniAssertSubscriber<Integer> subscriber = Uni.createFrom().<Integer> item(() -> {
+            calls.incrementAndGet();
+            throw new RuntimeException("boom");
+        })
+                .onFailure().retry().atMost(3)
+                .subscribe().withSubscriber(UniAssertSubscriber.create());
+
+        subscriber.awaitFailure();
+        assertThat(calls).hasValue(4); // initial subscription + 3 retries
+    }
 }