In Doctrine 2 can the Fetch Mode (Eager/Lazy etc.) be changed at runtime?

You can use setFetchMode() method of DQL to set mode.

See the documentation: https://web.archive.org/web/20120601032806/http://readthedocs.org/docs/doctrine-orm/en/latest/reference/dql-doctrine-query-language.html

If you want to use built-in repository methods (find(), findAll()), you're probably out of luck unless you set things to eagerly load in your annotations.

You'll probably want to use the query builder (or raw DQL) in some custom repository's method to force eager loading where you want it. Yes, you'll have to update that method as you add entities, but at least you'll always know what's going on in regards to lazy/eager loading, and you'll only need to maintain it all in one place.

I suppose the reason there's not some $eagerLoad flag to find(), etc, is because those are convenience methods for simple tasks. If you wanted to add such a flag, you'd have quickly get into situations where you'd want to limit recursive eager loading by depth. You'd also probably have to start worrying about cyclical references (any bidirectional association, for instance).