[#1514] Catch errors thrown while executing a transactions

Before, we were ignoring some errors if they were happening
in the worker provided to the transactions.
Because of this, the transaction wasn't always rollbacked or
closed.

Author: DavideD

hibernate-reactive-core/src/main/java/org/hibernate/reactive/mutiny/impl/MutinySessionImpl.java

@@ -508,7 +508,8 @@ Uni<T> execute(Function<Mutiny.Transaction, Uni<T>> work) {
 		 * roll back) and an error thrown by the work.
 		 */
 		Uni<T> executeInTransaction(Function<Mutiny.Transaction, Uni<T>> work) {
-			return work.apply( this )
+			return Uni.createFrom()
+					.deferred( () -> work.apply( this ) )
 					// only flush() if the work completed with no exception
 					.call( this::flush ).call( this::beforeCompletion )
 					// in the case of an exception or cancellation

hibernate-reactive-core/src/main/java/org/hibernate/reactive/mutiny/impl/MutinyStatelessSessionImpl.java

@@ -267,7 +267,7 @@ Uni<T> execute(Function<Mutiny.Transaction, Uni<T>> work) {
 		 * and an error thrown by the work.
 		 */
 		Uni<T> executeInTransaction(Function<Mutiny.Transaction, Uni<T>> work) {
-			return work.apply( this )
+			return Uni.createFrom().deferred( () -> work.apply( this ) )
 					// in the case of an exception or cancellation
 					// we need to rollback the transaction
 					.onFailure().call( this::rollback )

hibernate-reactive-core/src/main/java/org/hibernate/reactive/stage/impl/StageSessionImpl.java

@@ -46,6 +46,7 @@
 
 import static org.hibernate.reactive.util.impl.CompletionStages.applyToAll;
 import static org.hibernate.reactive.util.impl.CompletionStages.returnOrRethrow;
+import static org.hibernate.reactive.util.impl.CompletionStages.voidFuture;
 
 /**
  * Implements the {@link Stage.Session} API. This delegating class is
@@ -434,7 +435,7 @@ CompletionStage<T> execute(Function<Stage.Transaction, CompletionStage<T>> work)
 		 * roll back) and an error thrown by the work.
 		 */
 		CompletionStage<T> executeInTransaction(Function<Stage.Transaction, CompletionStage<T>> work) {
-			return work.apply( this )
+			return voidFuture().thenCompose( v -> work.apply( this ) )
 					// only flush() if the work completed with no exception
 					.thenCompose( result -> flush().thenApply( v -> result ) )
 					// have to capture the error here and pass it along,

hibernate-reactive-core/src/main/java/org/hibernate/reactive/stage/impl/StageStatelessSessionImpl.java

@@ -26,6 +26,7 @@
 import java.util.function.Function;
 
 import static org.hibernate.reactive.util.impl.CompletionStages.returnOrRethrow;
+import static org.hibernate.reactive.util.impl.CompletionStages.voidFuture;
 
 /**
  * Implements the {@link Stage.StatelessSession} API. This delegating
@@ -207,7 +208,8 @@ CompletionStage<T> execute(Function<Stage.Transaction, CompletionStage<T>> work)
 		 * and an error thrown by the work.
 		 */
 		CompletionStage<T> executeInTransaction(Function<Stage.Transaction, CompletionStage<T>> work) {
-			return work.apply( this )
+			return voidFuture()
+					.thenCompose( v -> work.apply( this ) )
 					// have to capture the error here and pass it along,
 					// since we can't just return a CompletionStage that
 					// rolls back the transaction from the handle() function