Fix incorrect handling of transactions using deferred constraints

src/Connection.php

@@ -1275,14 +1275,15 @@ public function transactional(Closure $func)
         $this->beginTransaction();
         try {
             $res = $func($this);
-            $this->commit();
-
-            return $res;
         } catch (Throwable $e) {
             $this->rollBack();
 
             throw $e;
         }
+
+        $this->commit();
+
+        return $res;
     }
 
     /**
@@ -1418,33 +1419,16 @@ public function commit()
 
         $connection = $this->getWrappedConnection();
 
-        if ($this->transactionNestingLevel === 1) {
-            $result = $this->doCommit($connection);
-        } elseif ($this->nestTransactionsWithSavepoints) {
-            $this->releaseSavepoint($this->_getNestedTransactionSavePointName());
-        }
-
-        --$this->transactionNestingLevel;
-
-        $eventManager = $this->getEventManager();
-
-        if ($eventManager->hasListeners(Events::onTransactionCommit)) {
-            Deprecation::trigger(
-                'doctrine/dbal',
-                'https://github.com/doctrine/dbal/issues/5784',
-                'Subscribing to %s events is deprecated.',
-                Events::onTransactionCommit,
-            );
-
-            $eventManager->dispatchEvent(Events::onTransactionCommit, new TransactionCommitEventArgs($this));
-        }
-
-        if ($this->autoCommit !== false || $this->transactionNestingLevel !== 0) {
-            return $result;
+        try {
+            if ($this->transactionNestingLevel === 1) {
+                $result = $this->doCommit($connection);
+            } elseif ($this->nestTransactionsWithSavepoints) {
+                $this->releaseSavepoint($this->_getNestedTransactionSavePointName());
+            }
+        } finally {
+            $this->updateTransactionStateAfterCommit();
         }
 
-        $this->beginTransaction();
-
         return $result;
     }
 
@@ -1461,7 +1445,11 @@ private function doCommit(DriverConnection $connection)
             $logger->startQuery('"COMMIT"');
         }
 
-        $result = $connection->commit();
+        try {
+            $result = $connection->commit();
+        } catch (Driver\Exception $e) {
+            throw $this->convertExceptionDuringQuery($e, 'COMMIT');
+        }
 
         if ($logger !== null) {
             $logger->stopQuery();
@@ -1470,6 +1458,30 @@ private function doCommit(DriverConnection $connection)
         return $result;
     }
 
+    private function updateTransactionStateAfterCommit(): void
+    {
+        --$this->transactionNestingLevel;
+
+        $eventManager = $this->getEventManager();
+
+        if ($eventManager->hasListeners(Events::onTransactionCommit)) {
+            Deprecation::trigger(
+                'doctrine/dbal',
+                'https://github.com/doctrine/dbal/issues/5784',
+                'Subscribing to %s events is deprecated.',
+                Events::onTransactionCommit,
+            );
+
+            $eventManager->dispatchEvent(Events::onTransactionCommit, new TransactionCommitEventArgs($this));
+        }
+
+        if ($this->autoCommit !== false || $this->transactionNestingLevel !== 0) {
+            return;
+        }
+
+        $this->beginTransaction();
+    }
+
     /**
      * Commits all current nesting transactions.
      *

src/Driver/OCI8/Connection.php

@@ -142,7 +142,7 @@ public function beginTransaction(): bool
 
     public function commit(): bool
     {
-        if (! oci_commit($this->connection)) {
+        if (! @oci_commit($this->connection)) {
             throw Error::new($this->connection);
         }
 

src/Driver/OCI8/Exception/Error.php

@@ -7,7 +7,9 @@
 use Doctrine\DBAL\Driver\AbstractException;
 
 use function assert;
+use function explode;
 use function oci_error;
+use function str_replace;
 
 /**
  * @internal
@@ -16,12 +18,26 @@
  */
 final class Error extends AbstractException
 {
+    private const CODE_TRANSACTION_ROLLED_BACK = 2091;
+
     /** @param resource $resource */
     public static function new($resource): self
     {
         $error = oci_error($resource);
         assert($error !== false);
 
-        return new self($error['message'], null, $error['code']);
+        $code    = $error['code'];
+        $message = $error['message'];
+        if ($code === self::CODE_TRANSACTION_ROLLED_BACK) {
+            // There's no way this can be unit-tested as it's impossible to mock $resource
+            //ORA-02091: transaction rolled back
+            //ORA-00001: unique constraint (DOCTRINE.GH3423_UNIQUE) violated
+            [$firstMessage, $secondMessage] = explode("\n", $message, 2);
+
+            [$code, $message] = explode(': ', $secondMessage, 2);
+            $code             = (int) str_replace('ORA-', '', $code);
+        }
+
+        return new self($message, null, $code);
     }
 }

src/Driver/PDO/Exception.php

@@ -7,15 +7,22 @@
 use Doctrine\DBAL\Driver\AbstractException;
 use PDOException;
 
+use function explode;
+use function str_replace;
+
 /**
  * @internal
  *
  * @psalm-immutable
  */
 final class Exception extends AbstractException
 {
+    private const CODE_TRANSACTION_ROLLED_BACK = 2091;
+
     public static function new(PDOException $exception): self
     {
+        $message = $exception->getMessage();
+
         if ($exception->errorInfo !== null) {
             [$sqlState, $code] = $exception->errorInfo;
 
@@ -25,6 +32,15 @@ public static function new(PDOException $exception): self
             $sqlState = null;
         }
 
-        return new self($exception->getMessage(), $sqlState, $code, $exception);
+        if ($code === self::CODE_TRANSACTION_ROLLED_BACK) {
+            //ORA-02091: transaction rolled back
+            //ORA-00001: unique constraint (DOCTRINE.GH3423_UNIQUE) violated
+            [$firstMessage, $secondMessage] = explode("\n", $message, 2);
+
+            [$code, $message] = explode(': ', $secondMessage, 2);
+            $code             = (int) str_replace('ORA-', '', $code);
+        }
+
+        return new self($message, $sqlState, $code, $exception);
     }
 }

src/Driver/PDO/PDOException.php

@@ -6,6 +6,11 @@
 
 use Doctrine\DBAL\Driver\Exception as DriverException;
 
+use function explode;
+use function is_numeric;
+use function str_replace;
+use function strpos;
+
 /**
  * @internal
  *
@@ -17,10 +22,26 @@ final class PDOException extends \PDOException implements DriverException
 
     public static function new(\PDOException $previous): self
     {
-        $exception = new self($previous->message, 0, $previous);
+        if (isset($previous->errorInfo[2]) && strpos($previous->errorInfo[2], 'OCITransCommit: ORA-02091') === 0) {
+            // With pdo_oci driver, the root-cause error is in the second line
+            //ORA-02091: transaction rolled back
+            //ORA-00001: unique constraint (DOCTRINE.GH3423_UNIQUE) violated
+            [$firstMessage, $secondMessage] = explode("\n", $previous->message, 2);
+
+            [$code, $message] = explode(': ', $secondMessage, 2);
+            $code             = (int) str_replace('ORA-', '', $code);
+        } else {
+            $message = $previous->message;
+            if (is_numeric($previous->code)) {
+                $code = (int) $previous->code;
+            } else {
+                $code = $previous->errorInfo[1] ?? 0;
+            }
+        }
+
+        $exception = new self($message, $code, $previous);
 
         $exception->errorInfo = $previous->errorInfo;
-        $exception->code      = $previous->code;
         $exception->sqlState  = $previous->errorInfo[0] ?? null;
 
         return $exception;

tests/Driver/PDO/ExceptionTest.php

@@ -53,4 +53,25 @@ public function testOriginalExceptionIsInChain(): void
     {
         self::assertSame($this->wrappedException, $this->exception->getPrevious());
     }
+
+    public function testExposesUnderlyingErrorOnOracle(): void
+    {
+        $pdoException = new PDOException(<<<'TEXT'
+OCITransCommit: ORA-02091: transaction rolled back
+ORA-00001: unique constraint (DOCTRINE.C1_UNIQUE) violated
+ (/private/tmp/php-20211003-35441-1sggrmq/php-8.0.11/ext/pdo_oci/oci_driver.c:410)
+TEXT);
+
+        $pdoException->errorInfo = [self::SQLSTATE, 2091,
+
+        ];
+
+        $exception = Exception::new($pdoException);
+
+        self::assertSame(1, $exception->getCode());
+        self::assertStringContainsString(
+            'unique constraint (DOCTRINE.C1_UNIQUE) violated',
+            $exception->getMessage(),
+        );
+    }
 }

tests/Functional/TransactionTest.php

@@ -5,7 +5,6 @@
 use Doctrine\DBAL\Driver\Exception as DriverException;
 use Doctrine\DBAL\Platforms\AbstractMySQLPlatform;
 use Doctrine\DBAL\Tests\FunctionalTestCase;
-use PDOException;
 
 use function sleep;
 
@@ -29,8 +28,8 @@ public function testCommitFalse(): void
         sleep(2); // during the sleep mysql will close the connection
 
         try {
-            self::assertFalse(@$this->connection->commit()); // we will ignore `MySQL server has gone away` warnings
-        } catch (PDOException $e) {
+            @$this->connection->commit(); // we will ignore `Packets out of order.` error
+        } catch (\Doctrine\DBAL\Exception\DriverException $e) {
             self::assertInstanceOf(DriverException::class, $e);
 
             /* For PDO, we are using ERRMODE EXCEPTION, so this catch should be