Fix inconsistency in PDO transaction state

This addresses an issue introduced by #4996 and reported in
https://bugs.php.net/bug.php?id=80260.

Now that PDO::inTransaction() reports the real transaction state
of the connection, there may be a mismatch with PDOs internal
transaction state (in_tcx). This is compounded by the fact that
MySQL performs implicit commits for DDL queries.

This patch fixes the issue by making beginTransaction/commit/rollBack
work on the real transaction state provided by the driver as well
(or falling back to in_tcx if the driver does not support it).

This does mean that writing something like

    $pdo->beginTransaction();
    $pdo->exec('CREATE DATABASE ...');
    $pdo->rollBack(); // <- illegal

will now result in an error, because the CREATE DATABASE already
committed the transaction. I believe this behavior is both correct
and desired -- otherwise, there is no indication that the code did
not behave correctly and the rollBack() was effectively ignored.
However, this is also a BC break.

Closes GH-6355.

1 files changed, 8 insertions, 3 deletions

diff --git a/ext/pdo_mysql/tests/pdo_mysql_commit.phpt b/ext/pdo_mysql/tests/pdo_mysql_commit.phpt
index 506be6475f..f88ae149fa 100644
--- a/ext/pdo_mysql/tests/pdo_mysql_commit.phpt
+++ b/ext/pdo_mysql/tests/pdo_mysql_commit.phpt
@@ -23,9 +23,14 @@ if (false == MySQLPDOTest::detect_transactional_mysql_engine($db))
         // DDL will issue an implicit commit
         $db->exec(sprintf('DROP TABLE IF EXISTS test_commit'));
         $db->exec(sprintf('CREATE TABLE test_commit(id INT) ENGINE=%s', MySQLPDOTest::detect_transactional_mysql_engine($db)));
-        if (true !== ($tmp = $db->commit())) {
-            printf("[002] No commit allowed? [%s] %s\n",
-                $db->errorCode(), implode(' ', $db->errorInfo()));
+        try {
+            $db->commit();
+            $failed = false;
+        } catch (PDOException $e) {
+            $failed = true;
+        }
+        if (!$failed) {
+            printf("[002] Commit should have failed\n");
         }
 
         // pdo_transaction_transitions should check this as well...