This bug was turned up by the test suite, running fsck in direct mode.
A repository was cloned, was put into direct mode, was fscked, and fsck
incorrectly said that no copy existed of a file, that was actually present
in origin.
This turned out to occur because fsck first did a Annex.Branch.change,
recording that it did not locally have the file. That was recorded in the
journal. Since neither the git annex direct not the fsck had yet needed to
read any info from the branch, but had only made changes to it, the
origin/git-annex branch was not yet merged in. So the journal got a
location log entry written to it, but this did not include
the location log info for the origin. When fsck then did a
Annex.Branch.get, it trusted the journal was cosnsitent, and returned it,
again w/o merging from origin/git-annex. This latter behavior is the
actual bug.
Refer to commit e9bfa8eaed for the thinking
behind it being ok to make a change to a file on the branch, without
first merging the branch. That thinking still stands. However, it means
that files in the journal cannot be trusted to be consistent if the branch
has not been merged. So, to fix, just enure the branch gets merged, even
when reading from the journal.
In tests, this does not seem to cause any extra merging. Except, of course,
in the one case described above. But git annex add, etc, are able to make
changes w/o first merging the branch.
git-annex allows managing files with git, without checking the file
contents into git. While that may seem paradoxical, it is useful when
dealing with files larger than git can currently easily handle, whether due
to limitations in memory, checksumming time, or disk space.
For documentation, see doc/ or <http://git-annex.branchable.com/>
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