[QUERY] How do you sort completions?

Hi,

I'm not able to sort completions for some weird reason. No matter what I order I insert stuff into COMPREPLY, bash seems to auto-sort them lexically. I tried to pass --sort='-committerdate' to git for-each-ref so I can get a sensible 'git checkout <TAB>' reply, and I'm very annoyed that it doesn't work.

I thought it was bash's complete builtin doing the implicit sorting, so I read the manual with no success. Is readline doing it? If so, why am I not getting the ordering even in zsh (which doesn't use readline)?

What am I missing?

Ram