Add Smallrye Mutiny support.

Closes #2471

src/main/java/org/springframework/data/repository/util/ReactiveWrapperConverters.java

@@ -17,6 +17,8 @@ package org.springframework.data.repository.util;
 
 import io.reactivex.Flowable;
 import io.reactivex.Maybe;
+import io.smallrye.mutiny.Multi;
+import io.smallrye.mutiny.Uni;
 import kotlinx.coroutines.flow.Flow;
 import kotlinx.coroutines.flow.FlowKt;
 import kotlinx.coroutines.reactive.ReactiveFlowKt;
@@ -104,6 +106,11 @@ public abstract class ReactiveWrapperConverters {
 			REACTIVE_WRAPPERS.add(FlowWrapper.INSTANCE);
 		}
 
+		if (ReactiveWrappers.isAvailable(ReactiveLibrary.MUTINY)) {
+			REACTIVE_WRAPPERS.add(UniWrapper.INSTANCE);
+			REACTIVE_WRAPPERS.add(MultiWrapper.INSTANCE);
+		}
+
 		registerConvertersIn(GENERIC_CONVERSION_SERVICE);
 	}
 
@@ -527,6 +534,43 @@ public abstract class ReactiveWrapperConverters {
 		}
 	}
 
+	/**
+	 * Wrapper for SmallRye Mutiny's {@link io.smallrye.mutiny.Uni}.
+	 */
+	private enum UniWrapper implements ReactiveTypeWrapper<io.smallrye.mutiny.Uni<?>> {
+
+		INSTANCE;
+
+		@Override
+		public Class<? super io.smallrye.mutiny.Uni<?>> getWrapperClass() {
+			return io.smallrye.mutiny.Uni.class;
+		}
+
+		@Override
+		public io.smallrye.mutiny.Uni<?> map(Object wrapper, Function<Object, Object> function) {
+			return ((io.smallrye.mutiny.Uni<?>) wrapper).map(function::apply);
+		}
+	}
+
+	/**
+	 * Wrapper for SmallRye Mutiny's {@link io.smallrye.mutiny.Multi}.
+	 */
+	private enum MultiWrapper implements ReactiveTypeWrapper<io.smallrye.mutiny.Multi<?>> {
+
+		INSTANCE;
+
+		@Override
+		public Class<? super io.smallrye.mutiny.Multi<?>> getWrapperClass() {
+			return io.smallrye.mutiny.Multi.class;
+		}
+
+		@Override
+		public io.smallrye.mutiny.Multi<?> map(Object wrapper, Function<Object, Object> function) {
+			return ((io.smallrye.mutiny.Multi<?>) wrapper).map(function::apply);
+		}
+	}
+
+
 	// -------------------------------------------------------------------------
 	// ReactiveStreams converters
 	// -------------------------------------------------------------------------

src/main/java/org/springframework/data/repository/util/ReactiveWrappers.java

@@ -83,6 +83,9 @@ public abstract class ReactiveWrappers {
 	private static final boolean KOTLIN_COROUTINES_PRESENT = ClassUtils.isPresent("kotlinx.coroutines.reactor.MonoKt",
 			ReactiveWrappers.class.getClassLoader());
 
+	private static final boolean MUTINY_PRESENT = ClassUtils.isPresent("io.smallrye.mutiny.Multi",
+			ReactiveWrappers.class.getClassLoader());
+
 	private ReactiveWrappers() {}
 
 	/**
@@ -104,7 +107,7 @@ public abstract class ReactiveWrappers {
 		 * @deprecated since 2.6, use RxJava 3 instead. To be removed with Spring Data 3.0.
 		 */
 		@Deprecated
-		RXJAVA2, RXJAVA3, KOTLIN_COROUTINES;
+		RXJAVA2, RXJAVA3, KOTLIN_COROUTINES, MUTINY;
 	}
 
 	/**
@@ -138,6 +141,8 @@ public abstract class ReactiveWrappers {
 				return RXJAVA3_PRESENT;
 			case KOTLIN_COROUTINES:
 				return PROJECT_REACTOR_PRESENT && KOTLIN_COROUTINES_PRESENT;
+			case MUTINY:
+				return MUTINY_PRESENT;
 			default:
 				throw new IllegalArgumentException(String.format("Reactive library %s not supported", reactiveLibrary));
 		}