This is actually tricky, 45bbf210a1 added
the escaping because it's needed for rsync that does go over ssh.
So I had to detect whether the remote's rsync url will use ssh or not,
and vary the escaping.
Avoids doing auto-merging in commands that don't need fully current
information from the git-annex branch. In particular, git annex add no
longer needs to auto-merge. Affected commands: Anything that doesn't
look up data from the branch, but does write a change to it.
It might seem counterintuitive that we can change a value without first
making sure we have the current value. This optimisation works because
these two sequences are equivilant:
1. pull from remote
2. union merge
3. read file from branch
4. modify file and write to branch
vs.
1. read file from branch
2. modify file and write to branch
3. pull from remote
4. union merge
After either sequence, the git-annex branch contains the same logical content
for the modified file. (Possibly with lines in a different order or
additional old lines of course).
More accurately, it was supported already when map uses git-annex-shell,
but not when it does not.
Note that the user name cannot be shell escaped using git-annex's current
approach for shell escaping. I tried and some shells like dash cannot
cd ~'joey'. Rest of directory is still shell escaped, not for security but
in case a directory has a space or other weird character.
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.)
