Starting with 11.0.6, using mysqli:// protocol no longer works, but the error message is obscure; improve the error message

[alberto56]

Is your feature request related to a problem? Please describe.

Until 11.0.5, using mysqli:// in the --db-url paramter of drush si always works, however starting 11.0.6 it gives a hard-to-understand error message.

For example:

composer require -W drush/drush:11.0.5
rm sites/default/settings.php
drush si -y --db-url "mysqli://root:drupal@mysql/drupal" standard
#  [success] Installation complete.  User name: admin  User password: ***
composer require -W drush/drush:11.0.6
rm sites/default/settings.php
drush si -y --db-url "mysqli://root:drupal@mysql/drupal" standard

The above results in:

In install.core.inc line 971:
                                                                                                                                                                
  Database name field is required.                                                                                                                              
  Database username field is required.                                                                                                                          
  Resolve all issues below to continue the installation. For help configuring your database server, see the <a href="https://www.drupal.org/docs/8/install">in  
  stallation handbook</a>, or contact your hosting provider.<div class="item-list"><ul><li>Failed to connect to your database server. The server reports the f  
  ollowing message: <em class="placeholder">SQLSTATE[HY000] [2002] No such file or directory</em>.<ul><li>Is the database server running?</li><li>Does the dat  
  abase exist or does the database user have sufficient privileges to create the database?</li><li>Have you entered the correct database name?</li><li>Have yo  
  u entered the correct username and password?</li><li>Have you entered the correct database hostname and port number?</li></ul></li></ul></div>                

Describe the solution you'd like

Instead of the error message above, perhaps it would be better to say something like:

[error] The mysqli://... protocol is deprecated; please use mysql:// instead.

Describe alternatives you've considered

The following works (mysql instead of mysqli):

drush si -y --db-url "mysql://root:drupal@mysql/drupal" standard

Additional context

The current error message can be confusing and I found the problem after a few hours of debugging.

[weitzman]

Did Drupal change or Drush changed?

[weitzman]

It would be good to link to the issue where mysqli became unusable.

[alberto56]

@weitzman I think Drush has changed because based on my tests mysqli works with Drupal 9 and Drush 11.0.5, but not with Drupal 9 and Drush 11.0.6.

I found a reference to mysqli in the diff between 11.0.5 and 11.0.6, this shows that #5070, which was meant to fix #5069, introduces this code change at line 610:

- 'driver'   => $url->scheme == 'mysqli' ? 'mysql' : $url->scheme,
+ 'driver'   => $url->scheme,

[weitzman]

Thanks for the research. And I'm sorry for the breakage ... The mysqli protocol isnt exactly deprecated. In that issue you linked to, the author is developing a drush driver for it. So we'll have to say something different in our error message.