Add commit result bool

lib/Doctrine/DBAL/Connection.php

@@ -1266,6 +1266,8 @@ public function commit()
             throw ConnectionException::commitFailedRollbackOnly();
         }
 
+        $result = true;
+
         $connection = $this->getWrappedConnection();
 
         $logger = $this->_config->getSQLLogger();
@@ -1275,7 +1277,7 @@ public function commit()
                 $logger->startQuery('"COMMIT"');
             }
 
-            $connection->commit();
+            $result = $connection->commit();
 
             if ($logger) {
                 $logger->stopQuery();
@@ -1293,12 +1295,12 @@ public function commit()
         --$this->transactionNestingLevel;
 
         if ($this->autoCommit !== false || $this->transactionNestingLevel !== 0) {
-            return true;
+            return $result;
         }
 
         $this->beginTransaction();
 
-        return true;
+        return $result;
     }
 
     /**

tests/Doctrine/Tests/DBAL/ConnectionTest.php

@@ -297,6 +297,36 @@ public function testCommitStartsTransactionInNoAutoCommitMode() : void
         self::assertTrue($conn->isTransactionActive());
     }
 
+    /**
+     * @dataProvider resultProvider
+     */
+    public function testCommitReturn(bool $expectedResult) : void
+    {
+        $driverConnection = $this->createMock(DriverConnection::class);
+        $driverConnection->expects($this->once())
+            ->method('commit')->willReturn($expectedResult);
+
+        $driverMock = $this->createMock(Driver::class);
+        $driverMock->expects($this->any())
+            ->method('connect')
+            ->will($this->returnValue($driverConnection));
+
+        $conn = new Connection([], $driverMock);
+
+        $conn->connect();
+        $conn->beginTransaction();
+
+        self::assertSame($expectedResult, $conn->commit());
+    }
+
+    /**
+     * @return bool[][]
+     */
+    public function resultProvider() : array
+    {
+        return [[true], [false]];
+    }
+
     /**
      * @group DBAL-81
      */

tests/Doctrine/Tests/DBAL/Functional/ConnectionTest.php

@@ -88,7 +88,7 @@ public function testTransactionNestingBehaviorWithSavepoints() : void
                 self::assertEquals(2, $this->connection->getTransactionNestingLevel());
                 $this->connection->beginTransaction();
                 self::assertEquals(3, $this->connection->getTransactionNestingLevel());
-                $this->connection->commit();
+                self::assertTrue($this->connection->commit());
                 self::assertEquals(2, $this->connection->getTransactionNestingLevel());
                 throw new Exception();
                 $this->connection->commit(); // never reached

tests/Doctrine/Tests/DBAL/Functional/TransactionTest.php

@@ -0,0 +1,39 @@
+<?php
+
+namespace Doctrine\Tests\DBAL\Functional;
+
+use Doctrine\DBAL\Platforms\MySqlPlatform;
+use Doctrine\Tests\DbalFunctionalTestCase;
+use function sleep;
+
+class TransactionTest extends DbalFunctionalTestCase
+{
+    protected function setUp() : void
+    {
+        parent::setUp();
+
+        if ($this->connection->getDatabasePlatform() instanceof MySqlPlatform) {
+            return;
+        }
+
+        $this->markTestSkipped('Restricted to MySQL.');
+    }
+
+    protected function tearDown() : void
+    {
+        $this->resetSharedConn();
+
+        parent::tearDown();
+    }
+
+    public function testCommitFalse() : void
+    {
+        $this->connection->query('SET SESSION wait_timeout=1');
+
+        $this->assertTrue($this->connection->beginTransaction());
+
+        sleep(2); // during the sleep mysql will close the connection
+
+        $this->assertFalse(@$this->connection->commit()); // we will ignore `MySQL server has gone away` warnings
+    }
+}