Commands that want to use it have to run their seek action inside
allowConcurrentOutput. Which seems reasonable; perhaps some future command
will want to support the -J flag but not use regions.
The region state moved from Annex to MessageState. This makes sense
organizationally, and note that some uses of onLocal use a different Annex
state, but pass the MessageState into it, which is what is needed.
Work around https://github.com/pcapriotti/optparse-applicative/issues/146
by not using action "file" and instead passing -o bashdefault -o default
to complete. This way, when optparse fails to complete a filename, bash
will fall back to regular filename completion.
Unfortunately, optparse-applicative does not provide a way to control the
options passed to complete, so I had to modify its generated completion script.
Note that for "git annex" command completion, git's completion script already
used -o bashdefault -o default, so that works too.
Note that I ran into a problem where parsing the global options looped
forever, eating memory. It was somehow caused by stacking
combineGlobalSetters inside a combineGlobalSetters. Maybe due to both
using "many"? Anyway, changed things to avoid that.
This works, and seems fairly robust. Clean get of 20 files at -J3. At -J10,
there are some messages about ssh multiplexing, probably due to a race
spinning up the ssh connection cacher. But, it manages to get all the files
ok regardless.
The progress bars are a scrambled mess though, due to bugs in
ascii-progress, which I've already filed. Particularly this one:
https://github.com/yamadapc/haskell-ascii-progress/issues/8
