Add transaction close support to async and reactive APIs (#1119) (#1124)

driver/clirr-ignored-differences.xml

@@ -31,4 +31,16 @@
         <method>org.neo4j.driver.Logger getLog(java.lang.Class)</method>
     </difference>
 
+    <difference>
+        <className>org/neo4j/driver/async/AsyncTransaction</className>
+        <differenceType>7012</differenceType>
+        <method>java.util.concurrent.CompletionStage closeAsync()</method>
+    </difference>
+
+    <difference>
+        <className>org/neo4j/driver/reactive/RxTransaction</className>
+        <differenceType>7012</differenceType>
+        <method>org.reactivestreams.Publisher close()</method>
+    </difference>
+
 </differences>

driver/src/main/java/org/neo4j/driver/async/AsyncTransaction.java

@@ -23,9 +23,9 @@
 import java.util.concurrent.Executor;
 import java.util.function.Function;
 
-import org.neo4j.driver.Session;
 import org.neo4j.driver.Query;
 import org.neo4j.driver.QueryRunner;
+import org.neo4j.driver.Session;
 
 /**
  * Logical container for an atomic unit of work.
@@ -90,4 +90,12 @@ public interface AsyncTransaction extends AsyncQueryRunner
      * be completed exceptionally when rollback fails.
      */
     CompletionStage<Void> rollbackAsync();
+
+    /**
+     * Close the transaction. If the transaction has been {@link #commitAsync() committed} or {@link #rollbackAsync() rolled back}, the close is optional and no
+     * operation is performed. Otherwise, the transaction will be rolled back by default by this method.
+     *
+     * @return new {@link CompletionStage} that gets completed with {@code null} when close is successful, otherwise it gets completed exceptionally.
+     */
+    CompletionStage<Void> closeAsync();
 }

driver/src/main/java/org/neo4j/driver/internal/async/InternalAsyncTransaction.java

@@ -45,7 +45,13 @@ public CompletionStage<Void> rollbackAsync()
     }
 
     @Override
-    public CompletionStage<ResultCursor> runAsync(Query query)
+    public CompletionStage<Void> closeAsync()
+    {
+        return tx.closeAsync();
+    }
+
+    @Override
+    public CompletionStage<ResultCursor> runAsync( Query query )
     {
         return tx.runAsync( query );
     }

driver/src/main/java/org/neo4j/driver/internal/reactive/InternalRxTransaction.java

@@ -76,7 +76,7 @@ public <T> Publisher<T> rollback()
         return createEmptyPublisher( tx::rollbackAsync );
     }
 
-    Publisher<Void> close()
+    public Publisher<Void> close()
     {
         return close( false );
     }

driver/src/main/java/org/neo4j/driver/reactive/RxTransaction.java

@@ -41,11 +41,19 @@ public interface RxTransaction extends RxQueryRunner
     <T> Publisher<T> commit();
 
     /**
-     * Rolls back the transaction.
-     * It completes without publishing anything if transaction is rolled back successfully.
-     * Otherwise, errors when there is any error to roll back.
+     * Rolls back the transaction. It completes without publishing anything if transaction is rolled back successfully. Otherwise, errors when there is any
+     * error to roll back.
+     *
      * @param <T> makes it easier to be chained after other publishers.
      * @return an empty publisher.
      */
     <T> Publisher<T> rollback();
+
+    /**
+     * Close the transaction. If the transaction has been {@link #commit() committed} or {@link #rollback() rolled back}, the close is optional and no operation
+     * is performed. Otherwise, the transaction will be rolled back by default by this method.
+     *
+     * @return new {@link Publisher} that gets completed when close is successful, otherwise an error is signalled.
+     */
+    Publisher<Void> close();
 }

testkit-backend/src/main/java/neo4j/org/testkit/backend/messages/requests/GetFeatures.java

@@ -59,13 +59,13 @@ public class GetFeatures implements TestkitRequest
             "Temporary:GetConnectionPoolMetrics",
             "Temporary:CypherPathAndRelationship",
             "Temporary:FullSummary",
-            "Temporary:ResultKeys"
+            "Temporary:ResultKeys",
+            "Temporary:TransactionClose"
     ) );
 
     private static final Set<String> SYNC_FEATURES = new HashSet<>( Arrays.asList(
             "Feature:Bolt:3.0",
             "Optimization:PullPipelining",
-            "Temporary:TransactionClose",
             "Feature:API:Result.List",
             "Optimization:ResultListFetchAll"
     ) );

testkit-backend/src/main/java/neo4j/org/testkit/backend/messages/requests/TransactionClose.java

@@ -21,12 +21,15 @@
 import lombok.Getter;
 import lombok.Setter;
 import neo4j.org.testkit.backend.TestkitState;
+import neo4j.org.testkit.backend.holder.AbstractTransactionHolder;
 import neo4j.org.testkit.backend.messages.responses.TestkitResponse;
 import neo4j.org.testkit.backend.messages.responses.Transaction;
 import reactor.core.publisher.Mono;
 
 import java.util.concurrent.CompletionStage;
 
+import org.neo4j.driver.async.AsyncTransaction;
+
 @Setter
 @Getter
 public class TransactionClose implements TestkitRequest
@@ -43,13 +46,19 @@ public TestkitResponse process( TestkitState testkitState )
     @Override
     public CompletionStage<TestkitResponse> processAsync( TestkitState testkitState )
     {
-        throw new UnsupportedOperationException();
+        return testkitState.getAsyncTransactionHolder( data.getTxId() )
+                           .thenApply( AbstractTransactionHolder::getTransaction )
+                           .thenCompose( AsyncTransaction::closeAsync )
+                           .thenApply( ignored -> createResponse( data.getTxId() ) );
     }
 
     @Override
     public Mono<TestkitResponse> processRx( TestkitState testkitState )
     {
-        throw new UnsupportedOperationException( "Operation not supported" );
+        return testkitState.getRxTransactionHolder( data.getTxId() )
+                           .map( AbstractTransactionHolder::getTransaction )
+                           .flatMap( tx -> Mono.fromDirect( tx.close() ) )
+                           .then( Mono.just( createResponse( data.getTxId() ) ) );
     }
 
     private Transaction createResponse( String txId )