This affected git annex view. It turns out that some other places
that use GIT_INDEX_FILE were already working around the bug. I removed the
workaround from Annex.Branch since the new workaround will do.
There's a potential race where the smudge filter is run at the same time an
object is being downloaded. If the download finished after the inAnnex
check, and before the keys db was updated, the associated file would not
get updated with the downloaded content.
I'm not sure this closes the race; it may only narrow the window. Problem
is, the keys database needs to communicate between two different processes.
In the case of the assistant, the transferkeys command is the other
process, and it closes the db handle after getting the file. So, it should
re-open the database and so see the update that the smudge filter has
written to it. But, what if the smudge filter takes a while to update the
database?
The keys database handle needs to be closed after merging, because the
smudge filter, in another process, updates the database. Old cached info
can be read for a while from the open database handle; closing it ensures
that the info written by the smudge filter is available.
This is pretty horribly ad-hoc, and it's especially nasty that the
transferrer closes the database every time.
Could not think of a foolproof way to detect if the old adjusted branch was
just behind the current branch. It's possible that the user amended the
adjusting commit at the head of the adjusted branch, for example.
I decided to bail in this situation, instead of just entering the old
branch, so that if git annex adjust succeeds the user is always in a
*current* adjusted branch, not some old and out of date one.
What could perhaps be done is enter the old branch and then update it. But
that seems too magical; the user may have rebased master or something or
may not want to propigate the changes from the old branch. Best to error
out.
