Today I revisited something from way back in [[day_7__bugfixes]].
Back then, it wasn't practical to run `git ls-files` on every
file the watcher noticed, to check if it was already in git. Revisiting
this, I found I could efficiently do that check at the same point it checks
`lsof`. When there's a lot of files being added, they're batched up at that
point, so it won't be calling `git ls-files` repeatedly.

Result: It's safe to mix use of the assistant with files stored in git
in the normal way. And it's safe to mix use of `git annex unlock` with
the assistant; it won't immediately re-lock files. Yay!

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Also fixed a crash in the committer, and made `git annex status` display
repository groups.

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Been thinking through where to store the [[transfer_control]] expressions.
Since repositories need to know about the transfer controls of other
remotes, storing them in `.git/config` isn't right. I thought it might be
nice to configure the expressions in `.gitattributes`, but it seems the
file format doesn't allow complicated multi-word attributes. Instead,
they'll be stored in the git-annex branch.
