The comments correctly noted that the remote could drop the key and
yet False be returned due to some problem that occurred afterwards.
For example, if it's a network remote, it could drop the key just
as the network goes down, and so things timeout and a nonzero exit
from ssh is propigated through and False returned.
However... Most of the time, this scenario will not have happened.
False will mean the remote was not available or could not drop the key
at all.
So, instead of assuming the worst, just trust the status we have.
If we get it wrong, and the scenario above happened, our location
log will think the remote has the key. But the remote's location
log (assuming it has one) will know it dropped it, and the next sync
will regain consistency.
For a special remote, with no location log, our location log will be wrong,
but this is no different than the situation where someone else dropped
the key from the remote and we've not synced with them. The standard
paranoia about not trusting the location log to be the last word about
whether a remote has a key will save us from these situations. Ie,
if we try to drop the file, we'll actively check the remote,
and determine the inconsistency then.
Clean up from 9769235d6b.
In some cases, looking up a remote by name even though it has no UUID is
desirable. This includes git annex sync, which can operate on remotes
without an annex, and XMPP pairing, which runs addRemote (with calls
byName) before the UUID of the XMPP remote has been configured in git.
Now getKeysPresent checks that the key's content, not only its directory,
exists. In direct mode, the inode cache file is used as a standin for the
content.
removeAnnex always removes the inode cache file, and drop and move --from
always call removeAnnex, even if the object does not seem to be inAnnex,
to ensure it's always deleted.
This reverts commit 57780cb3a4.
This was buggy, it caused the direct mode cache to be lost when dropping
keys, so when the file is gotten back, it's stored in indirect mode.
Note to self: Do not attempt bug fixes at 6 am!
These files were left behind, and made getKeysPresent find keys that were
not present. It would be expensive to make getKeysPresent check that the
actual key files are present (it just lists the directories). But that's not
needed if we just clean up the stale cache and mapping files.
To handle systems that were in direct mode and got switched back with stale
direct mode files, made cleanObjectLoc remove all files in the key's directory.
git annex unused will still list keys that are gone but for which the stale
direct mode files exists. To deal with that, made dropunused remove the key's
directory even if the key does not seem to be present.
* get/copy --auto: Transfer data even if it would exceed numcopies,
when preferred content settings want it.
* drop --auto: Fix dropping content when there are no preferred content
settings.
This was complicated quite a bit by needing to check numcopies. I optimised
that, so it only looks up numcopies once per file, no matter how many
remotes it checks to drop from. Although it did just occur to me that
it might be better to first check if it wants to drop content, and only
then check numcopies..
Now gitattributes are looked up, efficiently, in only the places that
really need them, using the same approach used for cat-file.
The old CheckAttr code seemed very fragile, in the way it streamed files
through git check-attr.
I actually found that cad8824852
was still deadlocking with ghc 7.4, at the end of adding a lot of files.
This should fix that problem, and avoid future ones.
The best part is that this removes withAttrFilesInGit and withNumCopies,
which were complicated Seek methods, as well as simplfying the types
for several other Seek methods that had a Backend tupled in.
Fscking a remote is now supported. It's done by retrieving
the contents of the specified files from the remote, and checking them,
so can be an expensive operation.
(Several optimisations are possible, to speed it up, of course.. This is
the slow and stupid remote fsck to start with.)
Still, if the remote is a special remote, or a git repository that you
cannot run fsck in locally, it's nice to have the ability to fsck it.
If you have any directory special remotes, now would be a good time to
fsck them, in case you were hit by the data loss bug fixed in the
previous release!
Made --from and --to command-specific options.
Added generic storage for values of command-specific options,
which allows removing some of the special case fields in AnnexState.
(Also added generic storage for command-specific flags, although there are
not yet any.)
Note that this storage uses a Map, so repeatedly looking up the same value
is slightly more expensive than looking up an AnnexState field. But, the
value can be looked up once in the seek stage, transformed as necessary,
and passed in a closure to the start stage, and this avoids that overhead.
Still, I'm hesitant to use this for things like force or fast flags.
It's probably best to reserve it for flags that are only used by a few
commands, or options like --from and --to that it's important only be
allowed to be used with commands that implement them, to avoid user
confusion.
git-annex-shell inannex now returns always 0, 1, or 100 (the last when
it's unclear if content is currently in the index due to it currently being
moved or dropped).
(Actual locking code still not yet written.)
The lock will only persist during the perform stage, so the content must
be removed from the annex then, rather than in the cleanup stage.
(No lock is actually taken yet.)
This new approach allows filtering out checks from the default set that are
not appropriate for a command, rather than having to list every check
that is appropriate. It also reduces some boilerplate.
Haskell does not define Eq for functions, so I had to go a long way around
with each check having a unique id. Meh.
get, drop: Added --auto option, which decides whether to get/drop content
as needed to work toward the configured numcopies.
The problem with bundling it up in optimize was that I then found I wanted
to run an optmize that did not drop files, only got them. Considered adding
a --only-get switch to it, but that seemed wrong. Instead, let's make
existing subcommands optionally smarter.
Note that the only actual difference between drop and drop --auto is that
the latter does not even try to drop a file if it knows of not enough
copies, and does not print any error messages about files it was unable to
drop.
It might be nice to make get avoid asking git for attributes when not in
auto mode. For now it always asks for attributes.
The only remaining vestiage of backends is different types of keys. These
are still called "backends", mostly to avoid needing to change user interface
and configuration. But everything to do with storing keys in different
backends was gone; instead different types of remotes are used.
In the refactoring, lots of code was moved out of odd corners like
Backend.File, to closer to where it's used, like Command.Drop and
Command.Fsck. Quite a lot of dead code was removed. Several data structures
became simpler, which may result in better runtime efficiency. There should
be no user-visible changes.
