Only "partially" because the journal is not locked during the merge, so
there's a small window where a different git-annex process could write info
to the journal that overwrites info taken from the merge.
That could be dealt with by locking, but the lock would really need to be
around the whole git-annex, to only let one run at a time. Otherwise, even
with the journal locked during the merge, another git-annex could already
be running, generate an overwriting change, and only store it in the journal
after the merge was complete. And similarly, two git-annex processes could
fight and overwrite each other's information independant of any merging.
So, a toplevel lock for git-annex may get added; it's something I've
considered before, as these potential, unlikely problems are not new.
(OTOH, fsck will deal with such problems.)
git is slow when the index file is large and has to be rewritten each time
a file is changed. To speed this up, added a journal where changes are
recorded before being fed into the index file and committed to the
git-annex branch. The entire journal can be fed into git with just 2
commands, and only one write of the index file.
That sucking sound is a whole page of code vanishing to be replaced with
return . catMaybes . map (logFileKey . takeFileName) =<< Branch.files
What can I say, git is my database, and haskell my copilot.
This fixes precommit, since in that hook, git sets the env var to write
to the lock file, which avoids git add failing due to the presence of the
lock file. (Took me a good hour and a half of confusion to figure this out.)
Test suite now passes 100%! Only the upgrade code still remains to be
written.
Otherwise, the location log changes are only staged in its index,
and this can confuse matters if pulling or cloning from the remote.
The test suite was failing because this wasn't done.
Do not set annex.version whenever any command is run. Just do it in init.
This ensures that, if a repo has annex.version=3, it has a git-annex
branch, so we don't have to run a command every time to check for the
branch.
Remove the old ad-hoc logic for v0 and v1, to simplify version checking.
stop changing gitattributes on init
create git-annex branch on init
ugly special case for init in a bare repository goes away, yay!
git annex init is also faster, at least in a large existing repo, as
it does not need to run the slow 'git add'
This will speed up typical cases like git-annex get, which currently
has to read the location log once, then read it a second time in order to
add a line to it. Since these reads now involve more than just reading
in a file, it seemed good to add a cache layer.
Only the most recent thing needs to be cached, because git-annex has
good locality; it operates on one file at a time, and only cares
about one item from the branch per file.
This is needed for robust handling of the git-annex branch. Since changes
are staged to its index as git-annex runs, and committed at the end,
it's possible that git-annex is interrupted, and leaves a dirty index.
When it next runs, it needs to be able to merge the git-annex branch
as necessary, without losing the existing changes in the index.
Note that this assumes that the git-annex branch is only modified by
git-annex. Any changes to it will be lost when git-annex updates the
branch. I don't see a good, inexpensive way to find changes in
the git-annex branch that arn't in the index, and union merging the
git-annex branch into the index every time would likewise be expensive.
