I've been disliking how the command seek actions were written for some
time, with their inversion of control and ugly workarounds.
The last straw to fix it was sync --content, which didn't fit the
Annex [CommandStart] interface well at all. I have not yet made it take
advantage of the changed interface though.
The crucial change, and probably why I didn't do it this way from the
beginning, is to make each CommandStart action be run with exceptions
caught, and if it fails, increment a failure counter in annex state.
So I finally remove the very first code I wrote for git-annex, which
was before I had exception handling in the Annex monad, and so ran outside
that monad, passing state explicitly as it ran each CommandStart action.
This was a real slog from 1 to 5 am.
Test suite passes.
Memory usage is lower than before, sometimes by a couple of megabytes, and
remains constant, even when running in a large repo, and even when
repeatedly failing and incrementing the error counter. So no accidental
laziness space leaks.
Wall clock speed is identical, even in large repos.
This commit was sponsored by an anonymous bitcoiner.
Previous test did not notice if there is a dangling symlink.
Also, if a directory exists with the same name as the imported file, that
cannot work, so don't let --force have an effect.
Note that the hash backends were made to stop printing a (checksum..)
message as part of this, since it showed up without a file when deciding
whether to act on a file. Should have probably removed that message a while
ago anyway, I suppose.
Note that --deduplicate currently checksums each file twice,
once to see if it's a known key, and once when importing it.
Perhaps this could be revisited and the extra checksum gotten rid of,
at the cost of not locking down the file when adding it.
This avoids some small overhead by only running the check once per command;
it also ensures that, even if the command doesn't find anything to run on,
it still fails to run when in a bare repo.
