Default local settings using incorrect namespace [Drupal\Core\Installer\Exception\InstallerException]

[b-sharpe]

Describe the bug
The current default.local.settings.php is using the incorrect namespace for the mysql driver, causing an error during installation.

To Reproduce
Steps to reproduce the behavior, ideally starting from a fresh install of BLT:

1. Run composer create-project acquia/drupal-recommended-project --no-interaction
2. Run blt setup

Detailed error output
[info] Undefined index: value install.core.inc:2300 [info] Array to string conversion install.core.inc:2300 In install.core.inc line 2304: [Drupal\Core\Installer\Exception\InstallerException] Database settings: Array

Additional context
If you comment out the DB settings and re-run blt setup, it will create the proper settings and work, in which you can see the different namespace.

Currently used in BLT:
'namespace' => 'Drupal\\Core\\Database\\Driver\\mysql',

What it should be:
'namespace' => 'Drupal\\Driver\\Database\\mysql',

[danepowell]

Makes sense, although I'm curious at what point this broke. Presumably in Drupal 9.0, but I'd expect to have found this before now.

[danepowell]

I see where the Drupal\\Driver namespace is defined, looks like it's been that way since D8.0: https://git.drupalcode.org/project/drupal/-/blob/9.1.x/core/composer.json#L173

But I can't reproduce the error you describe, and I've never heard of anyone having this problem before, which is a little puzzling given how long those namespaces have existed.

Regardless... I think the namespace is superfluous, so if it's causing anyone trouble perhaps we should just remove it: #4287

[loopy3025]

I had a note to add to this. I got this issue when I was upgrading from BLT 11 to BLT 12. I think maybe I chose to ignore the changes to the default local settings file when I did the upgrade. Changing my namespace as @b-sharpe suggested in the default local settings and re-running blt blt:init:settings allowed me to run blt drupal:install successfully.

Note I am running Docksal. This might also be a factor.

Adding exception trace so folks can find it with a search engine.

 [info] Undefined index: value install.core.inc:2289 [5.58 sec, 23.33 MB]
 [info] Array to string conversion install.core.inc:2289 [5.58 sec, 23.33 MB]

In install.core.inc line 2293:
                                                        
  [Drupal\Core\Installer\Exception\InstallerException]  
  Database settings:                                    
                                                        
  Array                                                 
                                                        
Exception trace:
  at /var/www/docroot/core/includes/install.core.inc:2293
 install_display_requirements() at /var/www/docroot/core/includes/install.core.inc:1080
 install_verify_requirements() at /var/www/docroot/core/includes/install.core.inc:694
 install_run_task() at /var/www/docroot/core/includes/install.core.inc:565
 install_run_tasks() at /var/www/docroot/core/includes/install.core.inc:118
 install_drupal() at /var/www/vendor/drush/drush/includes/drush.inc:213
 drush_call_user_func_array() at /var/www/vendor/drush/drush/includes/drush.inc:197
 drush_op() at /var/www/vendor/drush/drush/src/Commands/core/SiteInstallCommands.php:149
 Drush\Commands\core\SiteInstallCommands->install() at n/a:n/a
 call_user_func_array() at /var/www/vendor/consolidation/annotated-command/src/CommandProcessor.php:257
 Consolidation\AnnotatedCommand\CommandProcessor->runCommandCallback() at /var/www/vendor/consolidation/annotated-command/src/CommandProcessor.php:212
 Consolidation\AnnotatedCommand\CommandProcessor->validateRunAndAlter() at /var/www/vendor/consolidation/annotated-command/src/CommandProcessor.php:176
 Consolidation\AnnotatedCommand\CommandProcessor->process() at /var/www/vendor/consolidation/annotated-command/src/AnnotatedCommand.php:311
 Consolidation\AnnotatedCommand\AnnotatedCommand->execute() at /var/www/vendor/symfony/console/Command/Command.php:255
 Symfony\Component\Console\Command\Command->run() at /var/www/vendor/symfony/console/Application.php:1027
 Symfony\Component\Console\Application->doRunCommand() at /var/www/vendor/symfony/console/Application.php:273
 Symfony\Component\Console\Application->doRun() at /var/www/vendor/symfony/console/Application.php:149
 Symfony\Component\Console\Application->run() at /var/www/vendor/drush/drush/src/Runtime/Runtime.php:118
 Drush\Runtime\Runtime->doRun() at /var/www/vendor/drush/drush/src/Runtime/Runtime.php:49
 Drush\Runtime\Runtime->run() at /var/www/vendor/drush/drush/drush.php:72
 require() at /var/www/vendor/drush/drush/drush:4