constraint naming conflict, for same tables with different prefix

[moritz-h]

• Laravel Version: 5.3.4 (illuminate/database)
• PHP Version: 7.0.8
• Database Driver & Version: mysql 5.7.15

Description:

I create tables with a table prefix and set a foreign key constraint. (See reproduce example). Now i change the table prefix and want to create the same tables in the same database with a different prefix.
The second call ends with:
PHP Fatal error: Uncaught PDOException: SQLSTATE[23000]: Integrity constraint violation: 1022 Can't write; duplicate key in table '#sql-[...]

I checked the generated queries in the mysql logfile and the error occurs on the last of this 6 queries.

create table `foo_groups` (`id` bigint unsigned not null auto_increment primary key, `name` varchar(255) not null) default character set utf8mb4 collate utf8mb4_unicode_ci
create table `foo_users` (`id` bigint unsigned not null auto_increment primary key, `group_id` bigint unsigned not null, `name` varchar(255) not null) default character set utf8mb4 collate utf8mb4_unicode_ci
alter table `foo_users` add constraint `users_group_id_foreign` foreign key (`group_id`) references `foo_groups` (`id`)

create table `bar_groups` (`id` bigint unsigned not null auto_increment primary key, `name` varchar(255) not null) default character set utf8mb4 collate utf8mb4_unicode_ci
create table `bar_users` (`id` bigint unsigned not null auto_increment primary key, `group_id` bigint unsigned not null, `name` varchar(255) not null) default character set utf8mb4 collate utf8mb4_unicode_ci
alter table `bar_users` add constraint `users_group_id_foreign` foreign key (`group_id`) references `bar_groups` (`id`)

The name of the constraint is the same as in the third query, so i get the error above. So perhaps the solution is to somehow add the table prefix to the constraint name, so this name becomes unique again.

Steps To Reproduce:

Minimal example with this 2 files. Just composer install and then php test.php.
Then change 'prefix' => 'foo_', to 'prefix' => 'bar_', and run again php test.php

composer.json:

{
    "require": {
        "illuminate/database": "5.x"
    }
}

test.php:

<?php

use Illuminate\Database\Schema\Blueprint;
use Illuminate\Database\Capsule\Manager as Capsule;

require __DIR__.'/vendor/autoload.php';

$db_settings = [
    'driver' => 'mysql',
    'host' => '127.0.0.1',
    'port' => '3306',
    'database' => 'test',
    'username' => 'test',
    'password' => 'test',
    'charset' => 'utf8mb4',
    'collation' => 'utf8mb4_unicode_ci',
    'prefix' => 'foo_',
];

$capsule = new Capsule();
$capsule->addConnection($db_settings);
$capsule->bootEloquent();
$capsule->setAsGlobal();

$schema = $capsule->schema();

$schema->create('groups', function (Blueprint $table) {
    $table->bigIncrements('id');
    $table->string('name');
});

$schema->create('users', function (Blueprint $table) {
    $table->bigIncrements('id');
    $table->bigInteger('group_id')->unsigned();
    $table->string('name');
});
$schema->table('users', function (Blueprint $table) {
    $table->foreign('group_id')->references('id')->on('groups');
});

[themsaid]

This is a duplicate of #7889

But thank you for reporting :)