Fix commitTransaction() for failed transactions

Failed transactions are now properly cleaned up when calling commitTransaction(). Previously, failed transactions were left untouched on commit. This change aligns with PGJDBC's behavior.

[resolves #274]

Author: mp911de

pom.xml

@@ -33,6 +33,7 @@
 
     <properties>
         <assertj.version>3.16.1</assertj.version>
+        <awaitility.version>4.0.3</awaitility.version>
         <blockhound.version>1.0.3.RELEASE</blockhound.version>
         <hikari-cp.version>3.4.5</hikari-cp.version>
         <java.version>1.8</java.version>
@@ -186,6 +187,12 @@
             <version>${assertj.version}</version>
             <scope>test</scope>
         </dependency>
+        <dependency>
+            <groupId>org.awaitility</groupId>
+            <artifactId>awaitility</artifactId>
+            <version>${awaitility.version}</version>
+            <scope>test</scope>
+        </dependency>
         <dependency>
             <groupId>org.junit.jupiter</groupId>
             <artifactId>junit-jupiter-api</artifactId>

src/main/java/io/r2dbc/postgresql/PostgresqlConnection.java

@@ -107,7 +107,7 @@ public Mono<Void> close() {
     @Override
     public Mono<Void> commitTransaction() {
         return useTransactionStatus(transactionStatus -> {
-            if (OPEN == transactionStatus) {
+            if (IDLE != transactionStatus) {
                 return exchange("COMMIT");
             } else {
                 this.logger.debug("Skipping commit transaction because status is {}", transactionStatus);
@@ -336,9 +336,10 @@ private <T> Mono<T> withTransactionStatus(Function<TransactionStatus, T> f) {
         return Mono.defer(() -> Mono.just(f.apply(this.client.getTransactionStatus())));
     }
 
-    private Publisher<?> exchange(String sql) {
+    @SuppressWarnings("unchecked")
+    private <T> Publisher<T> exchange(String sql) {
         ExceptionFactory exceptionFactory = ExceptionFactory.withSql(sql);
-        return SimpleQueryMessageFlow.exchange(this.client, sql)
+        return (Publisher<T>) SimpleQueryMessageFlow.exchange(this.client, sql)
             .handle(exceptionFactory::handleErrorResponse)
             .as(Operators::discardOnCancel);
     }

src/main/java/io/r2dbc/postgresql/api/ErrorDetails.java

@@ -21,6 +21,7 @@
 import io.r2dbc.postgresql.message.backend.Field.FieldType;
 import io.r2dbc.postgresql.util.Assert;
 
+import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
@@ -89,7 +90,7 @@ public final class ErrorDetails {
 
 
     /**
-     * Creates a new exception.
+     * Create new {@link ErrorDetails} from {@link List} of {@link Field fields}.
      *
      * @param fields the fields to be used to populate the exception
      * @throws IllegalArgumentException if {@code fields} is {@code null}
@@ -120,6 +121,16 @@ private ErrorDetails(Map<FieldType, String> fields) {
         this.where = fields.get(WHERE);
     }
 
+    /**
+     * Create a new {@link ErrorDetails}
+     *
+     * @param message the error message
+     * @return the {@link ErrorDetails} object
+     */
+    public static ErrorDetails fromMessage(String message) {
+        return new ErrorDetails(Collections.singletonMap(MESSAGE, message));
+    }
+
     @Override
     public boolean equals(Object o) {
         if (this == o) {

src/test/java/io/r2dbc/postgresql/PostgresqlConnectionErrorsIntegrationTests.java

@@ -0,0 +1,56 @@
+/*
+ * Copyright 2020 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.r2dbc.postgresql;
+
+import io.r2dbc.postgresql.api.PostgresqlConnection;
+import io.r2dbc.postgresql.api.PostgresqlResult;
+import io.r2dbc.spi.R2dbcBadGrammarException;
+import org.awaitility.Awaitility;
+import org.junit.jupiter.api.Test;
+import reactor.test.StepVerifier;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * Integration tests for various error cases using {@link PostgresqlConnection}.
+ */
+final class PostgresqlConnectionErrorsIntegrationTests extends AbstractIntegrationTests {
+
+    @Test
+    void commitShouldRecoverFromFailedTransaction() {
+
+        this.connection.beginTransaction().as(StepVerifier::create).verifyComplete();
+        this.connection.createStatement("error").execute().flatMap(PostgresqlResult::getRowsUpdated).as(StepVerifier::create).verifyError(R2dbcBadGrammarException.class);
+
+        this.connection.commitTransaction().as(StepVerifier::create).verifyComplete();
+
+        Awaitility.await().until(() -> this.connection.isAutoCommit());
+        assertThat(this.connection.isAutoCommit()).isTrue();
+    }
+
+    @Test
+    void rollbackShouldRecoverFromFailedTransaction() {
+
+        this.connection.beginTransaction().as(StepVerifier::create).verifyComplete();
+        this.connection.createStatement("error").execute().flatMap(PostgresqlResult::getRowsUpdated).as(StepVerifier::create).verifyError(R2dbcBadGrammarException.class);
+
+        this.connection.rollbackTransaction().as(StepVerifier::create).verifyComplete();
+
+        assertThat(this.connection.isAutoCommit()).isTrue();
+    }
+
+}