Fix some cases where handling of keys with extensions varied depending on
the locale.
A filename with a unicode extension would before generate a key with an
extension in a unicode locale, but not in LANG=C, because the extension
was not all alphanumeric. Also the the length of the extension could be
counted differently depending on the locale.
In a non-unicode locale, git-annex migrate would see that the extension
was not all alphanumeric and want to "upgrade" it. Now that doesn't happen.
As far as backwards compatability, this does mean that unicode
extensions are counted by the number of bytes, not number of characters.
So, if someone is using unicode extensions, they may find git-annex
stops using them when adding files, because their extensions are too
long. Keys already in their repo with the "too long" extensions will
still work though, so this only prevents adding the same content with
the same extension generating the same key. Documented this by
documenting that annex.maxextensionlength is a number of bytes.
Also, if a filename has an extension that is not valid utf-8 and the
locale is utf-8, the extension will be allowed now, and an old
git-annex, in the same locale would not, and would also want to
"upgrade" that.
* Added sync --only-annex, which syncs the git-annex branch and annexed
content but leaves managing the other git branches up to you.
* Added annex.synconlyannex git config setting, which can also be set with
git-annex config to configure sync in all clones of the repo.
Use case is then the user has their own git workflow, and wants to use
git-annex without disrupting that, so they sync --only-annex to get the
git-annex stuff in sync in addition to their usual git workflow.
When annex.synconlyannex is set, --not-only-annex can be used to override
it.
It's not entirely clear what --only-annex --commit or --only-annex
--push should do, and I left that combination not documented because I
don't know if I might want to change the current behavior, which is that
such options do not override the --only-annex. My gut feeling is that
there is no good reasons to use such combinations; if you want to use
your own git workflow, you'll be doing your own committing and pulling
and pushing.
A subtle question is, how should import/export special remotes be handled?
Importing updates their remote tracking branch and merges it into master.
If --only-annex prevented that git branch stuff, then it would prevent
exporting to the special remote, in the case where it has changes that
were not imported yet, because there would be a unresolved conflict.
I decided that it's best to treat the fact that there's a remote tracking
branch for import/export as an implementation detail in this case. The more
important thing is that an import/export special remote is entirely annexed
content, and so it makes a lot of sense that --only-annex will still sync
with it.
