forget --drop-dead: Remove several classes of git-annex log files when they
become empty, further reducing the size of the git-annex branch.
Noticed while testing sameas uuid removal, but it could happen other times
too.
An empty log file is always treated by git-annex the same as no file
being present, and when the files are per-key, it can be a sizable space
saving to exclude them from the tree.
It would have been a lot less round-about to just make git annex dead
also add the uuids of sameas remotes to the trust.log as dead.
But, that would fail in the case where there's an unmerged other clone
that has a sameas remote that the current repo does not know about.
Then it would not get marked as dead.
Handling it at transition time avoids that scenario.
Note that the generation of trustmap' in dropDead should only
happen once, due to the partial application.
This solves the problem of sameas remotes trampling over per-remote
state. Used for:
* per-remote state, of course
* per-remote metadata, also of course
* per-remote content identifiers, because two remote implementations
could in theory generate the same content identifier for two different
peices of content
While chunk logs are per-remote data, they don't use this, because the
number and size of chunks stored is a common property across sameas
remotes.
External special remote had a complication, where it was theoretically
possible for a remote to send SETSTATE or GETSTATE during INITREMOTE or
EXPORTSUPPORTED. Since the uuid of the remote is typically generate in
Remote.setup, it would only be possible to pass a Maybe
RemoteStateHandle into it, and it would otherwise have to construct its
own. Rather than go that route, I decided to send an ERROR in this case.
It seems unlikely that any existing external special remote will be
affected. They would have to make up a git-annex key, and set state for
some reason during INITREMOTE. I can imagine such a hack, but it doesn't
seem worth complicating the code in such an ugly way to support it.
Unfortunately, both TestRemote and Annex.Import needed the Remote
to have a new field added that holds its RemoteStateHandle.
This is used by a special remote with sameas-uuid=
The remote's uuid is the sameas-uuid, but it needs to get
its RemoteConfig from the annex-config-uuid.
I found a way to avoid inheritance complicating anything outside of
Logs.Remote. It seems fine to require all inherited values to be
inherited and not set in the sameas remote's config. Since inherited
values will be used for stuff like encryption and perhaps chunking, which
control the actual content stored on the remote, it seems likely that
there will not be any reason to need them to vary between two remotes
that access the same underlying data store.
The newer version of containers is free; the minimum ghc version is
bundled with a newer version than that.
Initremote sets that, so after both initremote and enableremote,
the git config will be set.
Any remote that does not use Annex.SpecialRemote won't set
annex-config-uuid. But that's only Remote.Git, which doesn't use
RemoteConfig anyway.
initremote --sameas=remotename sets sameas-name and sameas-uuid
Using sameas-name rather than name prevents old git-annex initremote
from enabling a sameas remote by name, since it would not handle it
correctly.
