Deprecation: Doctrine\ORM\Mapping\UnderscoreNamingStrategy without making it number aware is deprecated

In most cases I would just answer this sort of question with a comment but I suspect other developers might run into this issue. I poked around a bit and could not find any explicit documentation on this issue. Perhaps because the DoctrineBundle is under the control of the Doctrine folks and not the Symfony developers. Or maybe I am just a bad searcher.

In any event, between 4.3 and 4.4 the service name for the underscore naming strategy was changed.

# doctrine.yaml
orm:
  # 4.3
  naming_strategy: doctrine.orm.naming_strategy.underscore
  # 4.4
  naming_strategy: doctrine.orm.naming_strategy.underscore_number_aware

And a depreciation message was added to warn developers to change the name. Would have been nice if the message was just a tiny bit more explicit but oh well. So if you are upgrading an existing app to 4.4 and beyond then you will probably need to manually edit your doctrine.yaml file to make the depreciation message go away.

Some more info (thanks @janh) on why the change was made: https://github.com/doctrine/orm/blob/2.8.x/UPGRADE.md#deprecated-number-unaware-doctrineormmappingunderscorenamingstrategy https://github.com/doctrine/orm/issues/7855

Still not really clear on why "they" chose to do things this way but oh well. You probably want to run "bin/console doctrine:schema:update --dump-sql" just to see if this impacts your database column names and adjust accordingly. The changes has been out for several weeks now and there does not seem to be many howls of outrage over the change so I guess most column names don't have embedded numbers. So far at least.