refactor: Proper wrap retryable exceptions in TransactionSystemException.

This avoids an attempted rollback when the commit already failed which will lead to an illegal state exception otherwise, which will completely throw off the transaction system.
Discovered through an internal card.

Author: michael-simons

src/main/java/org/springframework/data/neo4j/core/support/RetryExceptionPredicate.java

@@ -25,6 +25,7 @@
 import org.neo4j.driver.exceptions.SessionExpiredException;
 import org.neo4j.driver.exceptions.TransientException;
 import org.springframework.dao.TransientDataAccessResourceException;
+import org.springframework.transaction.TransactionSystemException;
 
 
 /**
@@ -52,13 +53,17 @@ public boolean test(Throwable throwable) {
 			return true;
 		}
 
+		if (throwable instanceof TransactionSystemException && throwable.getCause() != null) {
+			throwable = throwable.getCause();
+		}
+
 		if (throwable instanceof IllegalStateException) {
 			String msg = throwable.getMessage();
 			return msg != null && RETRYABLE_ILLEGAL_STATE_MESSAGES.contains(msg);
 		}
 
 		Throwable ex = throwable;
-		if (throwable instanceof TransientDataAccessResourceException) {
+		if (throwable instanceof TransientDataAccessResourceException || throwable instanceof TransactionSystemException) {
 			ex = throwable.getCause();
 		}
 

src/main/java/org/springframework/data/neo4j/core/transaction/Neo4jTransactionManager.java

@@ -23,6 +23,8 @@
 import org.neo4j.driver.Session;
 import org.neo4j.driver.Transaction;
 import org.neo4j.driver.TransactionConfig;
+import org.neo4j.driver.exceptions.Neo4jException;
+import org.neo4j.driver.exceptions.RetryableException;
 import org.springframework.beans.BeansException;
 import org.springframework.context.ApplicationContext;
 import org.springframework.context.ApplicationContextAware;
@@ -338,10 +340,17 @@ protected void doResume(@Nullable Object transaction, Object suspendedResources)
 	@Override
 	protected void doCommit(DefaultTransactionStatus status) throws TransactionException {
 
-		Neo4jTransactionObject transactionObject = extractNeo4jTransaction(status);
-		Neo4jTransactionHolder transactionHolder = transactionObject.getRequiredResourceHolder();
-		Collection<Bookmark> newBookmarks = transactionHolder.commit();
-		this.bookmarkManager.resolve().updateBookmarks(transactionHolder.getBookmarks(), newBookmarks);
+		try {
+			Neo4jTransactionObject transactionObject = extractNeo4jTransaction(status);
+			Neo4jTransactionHolder transactionHolder = transactionObject.getRequiredResourceHolder();
+			Collection<Bookmark> newBookmarks = transactionHolder.commit();
+			this.bookmarkManager.resolve().updateBookmarks(transactionHolder.getBookmarks(), newBookmarks);
+		} catch (Neo4jException ex) {
+			if (ex instanceof RetryableException) {
+				throw new TransactionSystemException(ex.getMessage(), ex);
+			}
+			throw ex;
+		}
 	}
 
 	@Override

src/main/java/org/springframework/data/neo4j/core/transaction/ReactiveNeo4jTransactionManager.java

@@ -21,6 +21,7 @@
 import org.apiguardian.api.API;
 import org.neo4j.driver.Driver;
 import org.neo4j.driver.TransactionConfig;
+import org.neo4j.driver.exceptions.RetryableException;
 import org.neo4j.driver.reactivestreams.ReactiveSession;
 import org.neo4j.driver.reactivestreams.ReactiveTransaction;
 import org.springframework.beans.BeansException;
@@ -35,6 +36,7 @@
 import org.springframework.transaction.NoTransactionException;
 import org.springframework.transaction.TransactionDefinition;
 import org.springframework.transaction.TransactionException;
+import org.springframework.transaction.TransactionSystemException;
 import org.springframework.transaction.reactive.AbstractReactiveTransactionManager;
 import org.springframework.transaction.reactive.GenericReactiveTransaction;
 import org.springframework.transaction.reactive.TransactionSynchronizationManager;
@@ -326,6 +328,7 @@ protected Mono<Void> doCommit(TransactionSynchronizationManager transactionSynch
 				.getRequiredResourceHolder();
 		return holder.commit()
 				.doOnNext(bookmark -> bookmarkManager.resolve().updateBookmarks(holder.getBookmarks(), bookmark))
+				.onErrorMap(e -> e instanceof RetryableException, e -> new TransactionSystemException(e.getMessage(), e))
 				.then();
 	}
 

src/test/java/org/springframework/data/neo4j/integration/imperative/QuerydslNeo4jPredicateExecutorIT.java

@@ -323,7 +323,7 @@ void fluentFindAllWithLimitShouldWork(@Autowired QueryDSLPersonRepository reposi
 		Predicate predicate = Expressions.predicate(Ops.EQ, firstNamePath, Expressions.asString("Helge"))
 				.or(Expressions.predicate(Ops.EQ, lastNamePath, Expressions.asString("B.")));
 		List<Person> people = repository.findBy(predicate,
-				q -> q.limit(1)).all();
+				q -> q.sortBy(Sort.by("firstName").descending()).limit(1)).all();
 
 		assertThat(people).hasSize(1);
 		assertThat(people).extracting(Person::getFirstName).containsExactly("Helge");