3.x: Add Single/Completable retryUntil + marbles

src/main/java/io/reactivex/rxjava3/core/Completable.java

@@ -2317,6 +2317,26 @@ public final Completable retry(@NonNull Predicate<? super Throwable> predicate)
         return fromPublisher(toFlowable().retry(predicate));
     }
 
+    /**
+     * Retries until the given stop function returns {@code true}.
+     * <p>
+     * <img width="640" height="354" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Completable.retryUntil.png" alt="">
+     * <dl>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code retryUntil} does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     * @param stop the function that should return {@code true} to stop retrying
+     * @return the new {@code Completable} instance
+     * @throws NullPointerException if {@code stop} is {@code null}
+     */
+    @CheckReturnValue
+    @NonNull
+    @SchedulerSupport(SchedulerSupport.NONE)
+    public final Completable retryUntil(@NonNull BooleanSupplier stop) {
+        Objects.requireNonNull(stop, "stop is null");
+        return retry(Long.MAX_VALUE, Functions.predicateReverseFor(stop));
+    }
+
     /**
      * Returns a {@code Completable} which given a {@link Publisher} and when this {@code Completable} emits an error, delivers
      * that error through a {@link Flowable} and the {@code Publisher} should signal a value indicating a retry in response

src/main/java/io/reactivex/rxjava3/core/Maybe.java

@@ -4433,6 +4433,8 @@ public final Maybe<T> retry(@NonNull Predicate<? super Throwable> predicate) {
 
     /**
      * Retries until the given stop function returns {@code true}.
+     * <p>
+     * <img width="640" height="285" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.retryUntil.png" alt="">
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code retryUntil} does not operate by default on a particular {@link Scheduler}.</dd>

src/main/java/io/reactivex/rxjava3/core/Single.java

@@ -3747,6 +3747,26 @@ public final Single<T> retry(@NonNull Predicate<? super Throwable> predicate) {
         return toSingle(toFlowable().retry(predicate));
     }
 
+    /**
+     * Retries until the given stop function returns {@code true}.
+     * <p>
+     * <img width="640" height="364" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.retryUntil.png" alt="">
+     * <dl>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code retryUntil} does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     * @param stop the function that should return {@code true} to stop retrying
+     * @return the new {@code Single} instance
+     * @throws NullPointerException if {@code stop} is {@code null}
+     */
+    @CheckReturnValue
+    @NonNull
+    @SchedulerSupport(SchedulerSupport.NONE)
+    public final Single<T> retryUntil(@NonNull BooleanSupplier stop) {
+        Objects.requireNonNull(stop, "stop is null");
+        return retry(Long.MAX_VALUE, Functions.predicateReverseFor(stop));
+    }
+
     /**
      * Re-subscribes to the current {@code Single} if and when the {@link Publisher} returned by the handler
      * function signals a value.

src/test/java/io/reactivex/rxjava3/completable/CompletableRetryTest.java

@@ -20,6 +20,7 @@
 import org.junit.Test;
 
 import io.reactivex.rxjava3.core.*;
+import io.reactivex.rxjava3.exceptions.TestException;
 import io.reactivex.rxjava3.functions.*;
 import io.reactivex.rxjava3.internal.functions.Functions;
 
@@ -113,4 +114,42 @@ public void retryTimesPredicateWithZeroRetries() {
 
         assertEquals(1, numberOfSubscribeCalls.get());
     }
+
+    @Test
+    public void untilTrueEmpty() {
+        Completable.complete()
+        .retryUntil(() -> true)
+        .test()
+        .assertResult();
+    }
+
+    @Test
+    public void untilFalseEmpty() {
+        Completable.complete()
+        .retryUntil(() -> false)
+        .test()
+        .assertResult();
+    }
+
+    @Test
+    public void untilTrueError() {
+        Completable.error(new TestException())
+        .retryUntil(() -> true)
+        .test()
+        .assertFailure(TestException.class);
+    }
+
+    @Test
+    public void untilFalseError() {
+        AtomicInteger counter = new AtomicInteger();
+        Completable.defer(() -> {
+            if (counter.getAndIncrement() == 0) {
+                return Completable.error(new TestException());
+            }
+            return Completable.complete();
+        })
+        .retryUntil(() -> false)
+        .test()
+        .assertResult();
+    }
 }

src/test/java/io/reactivex/rxjava3/maybe/MaybeRetryTest.java

@@ -21,6 +21,7 @@
 import org.junit.Test;
 
 import io.reactivex.rxjava3.core.*;
+import io.reactivex.rxjava3.exceptions.TestException;
 import io.reactivex.rxjava3.functions.Predicate;
 import io.reactivex.rxjava3.internal.functions.Functions;
 
@@ -120,4 +121,58 @@ public void retryTimesPredicateWithZeroRetries() {
 
         assertEquals(1, numberOfSubscribeCalls.get());
     }
+
+    @Test
+    public void untilTrueJust() {
+        Maybe.just(1)
+        .retryUntil(() -> true)
+        .test()
+        .assertResult(1);
+    }
+
+    @Test
+    public void untilFalseJust() {
+        Maybe.just(1)
+        .retryUntil(() -> false)
+        .test()
+        .assertResult(1);
+    }
+
+    @Test
+    public void untilTrueEmpty() {
+        Maybe.empty()
+        .retryUntil(() -> true)
+        .test()
+        .assertResult();
+    }
+
+    @Test
+    public void untilFalseEmpty() {
+        Maybe.empty()
+        .retryUntil(() -> false)
+        .test()
+        .assertResult();
+    }
+
+    @Test
+    public void untilTrueError() {
+        Maybe.error(new TestException())
+        .retryUntil(() -> true)
+        .test()
+        .assertFailure(TestException.class);
+    }
+
+    @Test
+    public void untilFalseError() {
+        AtomicInteger counter = new AtomicInteger();
+        Maybe.defer(() -> {
+            if (counter.getAndIncrement() == 0) {
+                return Maybe.error(new TestException());
+            }
+            return Maybe.just(1);
+        })
+        .retryUntil(() -> false)
+        .test()
+        .assertResult(1);
+    }
 }

src/test/java/io/reactivex/rxjava3/single/SingleRetryTest.java

@@ -21,6 +21,7 @@
 import org.junit.Test;
 
 import io.reactivex.rxjava3.core.*;
+import io.reactivex.rxjava3.exceptions.TestException;
 import io.reactivex.rxjava3.functions.Predicate;
 import io.reactivex.rxjava3.internal.functions.Functions;
 
@@ -120,4 +121,42 @@ public void retryTimesPredicateWithZeroRetries() {
 
         assertEquals(1, numberOfSubscribeCalls.get());
     }
+
+    @Test
+    public void untilTrueJust() {
+        Single.just(1)
+        .retryUntil(() -> true)
+        .test()
+        .assertResult(1);
+    }
+
+    @Test
+    public void untilFalseJust() {
+        Single.just(1)
+        .retryUntil(() -> false)
+        .test()
+        .assertResult(1);
+    }
+
+    @Test
+    public void untilTrueError() {
+        Single.error(new TestException())
+        .retryUntil(() -> true)
+        .test()
+        .assertFailure(TestException.class);
+    }
+
+    @Test
+    public void untilFalseError() {
+        AtomicInteger counter = new AtomicInteger();
+        Single.defer(() -> {
+            if (counter.getAndIncrement() == 0) {
+                return Single.error(new TestException());
+            }
+            return Single.just(1);
+        })
+        .retryUntil(() -> false)
+        .test()
+        .assertResult(1);
+    }
 }