Eg, when git commit runs the smudge filter.
Commit 428c91606b introduced the crash,
as write-tree fails in those situations. Now it will work, and git-annex
always gets up-to-date information even in those situations. It does
need to do a bit more work, each time git-annex is run with the index
locked. Although if the index is unmodified from the last time
write-tree succeeded, that work is avoided.
Before only unlocked files were included.
The initial scan now scans for locked as well as unlocked files. This
does mean it gets a little bit slower, although I optimised it as well
as I think it can be.
reconcileStaged changed to diff from the current index to the tree of
the previous index. This lets it handle deletions as well, removing
associated files for both locked and unlocked files, which did not
always happen before.
On upgrade, there will be no recorded previous tree, so it will diff
from the empty tree to current index, and so will fully populate the
associated files, as well as removing any stale associated files
that were present due to them not being removed before.
reconcileStaged now does a bit more work. Most of the time, this will
just be due to running more often, after some change is made to the
index, and since there will be few changes since the last time, it will
not be a noticable overhead. What may turn out to be a noticable
slowdown is after changing to a branch, it has to go through the diff
from the previous index to the new one, and if there are lots of
changes, that could take a long time. Also, after adding a lot of files,
or deleting a lot of files, or moving a large subdirectory, etc.
Command.Lock used removeAssociatedFile, but now that's wrong because a
newly locked file still needs to have its associated file tracked.
Command.Rekey used removeAssociatedFile when the file was unlocked.
It could remove it also when it's locked, but it is not really
necessary, because it changes the index, and so the next time git-annex
run and accesses the keys db, reconcileStaged will run and update it.
There are probably several other places that use addAssociatedFile and
don't need to any more for similar reasons. But there's no harm in
keeping them, and it probably is a good idea to, if only to support
mixing this with older versions of git-annex.
However, mixing this and older versions does risk reconcileStaged not
running, if the older version already ran it on a given index state. So
it's not a good idea to mix versions. This problem could be dealt with
by changing the name of the gitAnnexKeysDbIndexCache, but that would
leave the old file dangling, or it would need to keep trying to remove
it.
They're only needed to cover a gc edge case, and it's better someone
gets caught by that edge case than that someone who does not know about
them ends up with a filtered git-annex branch that contains such a tree
when some of the files listed in it are ones they wanted to *remove*
from the repository.
It's not currently possible to exclude a sameas repo using its
annex-config-uuid. (Remote.nameToUUID rejects them).
Since there's no real documented way to learn those, this seems ok, at
least for now. Also it avoids the problem of someone excluding the
parent but including the sameas, which would probably make the sameas
repo not usable when using the filtered branch.
