Description:
------------
PHP PDO mysqlnd ignores InnoDB deadlock errors (1213) when ATTR_EMULATE_PREPARES = false

When a deadlock is detected the current transaction is discarded without any indication that something went wrong. Making it possible to have hard-to-find bugs where one sometimes seems to "mysteriously" lose data when inserting into or updating the database.

Tested on:
Centos 7, 5.5.56-MariaDB MariaDB Server
PHP 7.3.0alpha4 mysqlnd 5.0.12-dev (remi-safe)
PHP 7.2.8 mysqlnd 5.0.12-dev (remi-safe)
PHP 7.1.8 mysqlnd 5.0.12-dev (centos-sclo-rh)
PHP 5.4.16 mysqlnd 5.0.10 (centos-sclo-rh)


Test script:
---------------
CREATE DATABASE test CHARACTER SET 'utf8' COLLATE 'utf8_unicode_ci';
USE test;
CREATE TABLE test (
    id INT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY,
    data MEDIUMTEXT NULL
) ENGINE = InnoDB;

<?php

$password = 'password';

$dbh = new \PDO("mysql:host=localhost;dbname=test", 'root', $password,
    [\PDO::ATTR_ERRMODE => \PDO::ERRMODE_EXCEPTION, \PDO::ATTR_EMULATE_PREPARES => false]);

$dbh->query('SET TRANSACTION ISOLATION LEVEL SERIALIZABLE');
$dbh->beginTransaction();
$dbh->prepare("INSERT INTO test (data) VALUES (:data);")
    ->execute(['data' => 'a']);

sleep(5);

$sth = $dbh->prepare("SELECT id, data FROM test WHERE 1");
var_dump($sth->execute(), $sth->fetchAll(), $dbh->commit());


Expected result:
----------------
Shell 1:
[jan@localhost ~]$ php test.php 
bool(true)
array(1) {
  [0] =>
  array(4) {
    'id' =>
    int(1)
    [0] =>
    int(1)
    'data' =>
    string(1) "a"
    [1] =>
    string(1) "a"
  }
}
bool(true)

Shell 2: (started 2 seconds after 1st)
[jan@localhost ~]$ php test.php 
PHP Fatal error:  Uncaught PDOException: SQLSTATE[40001]: Serialization failure: 1213 Deadlock found when trying to get lock; try restarting transaction in /home/jan/test.php:16
Stack trace:
#0 /home/jan/test.php(16): PDOStatement->execute()
#1 {main}
  thrown in /home/jan/test.php on line 16


Actual result:
--------------
Shell 1:
[jan@localhost ~]$ php test.php 
bool(true)
array(1) {
  [0] =>
  array(4) {
    'id' =>
    int(1)
    [0] =>
    int(1)
    'data' =>
    string(1) "a"
    [1] =>
    string(1) "a"
  }
}
bool(true)

Shell 2: (started 2 seconds after 1st)
[jan@localhost ~]$ php test.php 
bool(true)
array(0) {
}
bool(true)