Recently, I thought, that it would be great to sort by default tags from fzTagPlugin by weight anywhere. So I started to look, as I remembered to read a while ago about an option that can be set on relations. I finally found it but... it's not suitable for many-to-many relations, which is used for tags.
It took me two days to find that article (Did you know that...) again, and there, in the comments I found what I was looking for. It is even simpler than setting orderBy for relation, you can set up orderBy for entire model:
Now, after building up model, doctrine adds that sorting to your query unless you set up your own orderBy settings. Everything looks and works great, unless you actually try to retrieve tagged object and tags in one query.
After that Doctrine tries to sort both by weight both tags and association table.
SELECT * FROM object o LEFT JOIN object_fz_tag o2 ON (o.id = o2.id) LEFT JOIN fz_tag f ON f.id = o2.tag_id ORDER BY f.weight DESC, o2.weight DESC;
And even if it worked, would you dare to guess how would object's list looked like? Well... it would probably be sorted by tag's weight, unless you'd add your own order by. But then would have to set orderBy on tags as well.