It did not seem possible to avoid creating a git-annex branch while
git-remote-annex is running. Special remotes can even store their own
state in it. So instead, if it didn't exist before git-remote-annex
created it, it deletes it at the end.
This does possibly allow a race condition, where git-annex init and
perhaps other git-annex writing commands are run, that writes to the
git-annex branch, at the same time a git-remote-annex process is being
run by git fetch/push with a full annex:: url. Those writes would be
lost. If the repository has already been initialized before
git-remote-annex, that race won't happen. So it's pretty unlikely.
Sponsored-by: Graham Spencer on Patreon
Also support using annex:: urls that specify the whole special remote
config.
Both of these cases need a special remote to be initialized enough to
use it, which means writing to .git/config but not to the git-annex
branch. When cloning, the remote is left set up in .git/config,
so further use of it, by git-annex or git-remote-annex will work. When
using git with an annex:: url, a temporary remote is written to
.git/config, but then removed at the end.
While that's a little bit ugly, the fact is that the Remote interface
expects that it's ok to set git configs of the remote that is being
initialized. And it's nowhere near as ugly as the alternative of making
a temporary git repository and initializing the special remote in there.
Cloning from a repository that does not contain a git-annex branch and
then later running git-annex init is currently broken, although I've
gotten most of the way there to supporting it.
See cleanupInitialization FIXME.
Special shout out to git clone for running gitremote-helpers with
GIT_DIR set, but not in the git repository and with GIT_WORK_TREE not
set. Resulting in needing the fixupRepo hack.
Sponsored-by: unqueued on Patreon
Tested using a manually populated directory special remote.
Pushing is still to be done. So is fetching from special remotes
configured via the annex:: url.
Sponsored-by: Brock Spratlen on Patreon
Making GITBUNDLE be in the backend list allows those keys to be
hashed to verify, both when git-remote-annex downloads them, and by other
transfers and by git fsck.
GITMANIFEST is not in the backend list, because those keys will never be
stored in .git/annex/objects and can't be verified in any case.
This does mean that git-annex version will include GITBUNDLE in the list
of backends.
Also documented these in backends.mdwn
Sponsored-by: Kevin Mueller on Patreon
Not quite there yet.
Also, changed the format of GITBUNDLE keys to use only one '-'
after the UUID. A sha256 does not contain that character, so can just
split at the last one.
Amusingly, the sha256 will probably not actually be verified. A git
bundle contains its own checksums that git uses to verify it. And if
someone wanted to replace the content of a GITBUNDLE object, they
could just edit the manifest to use a new one whose sha256 does verify.
Sponsored-by: Nicholas Golder-Manning
Changed the format of the url to use annex: rather than annex::
The reason is that in the future, might want to support an url that
includes an uriAuthority part, eg:
annex://foo@example.com:42/358ff77e-0bc3-11ef-bc49-872e6695c0e3?type=directory&encryption=none&directory=/mnt/foo/"
To parse that foo@example.com:42 as an uriAuthority it needs to start with
annex: rather than annex::
That would also need something to be done with uriAuthority, and also
the uriPath (the UUID) is prefixed with "/" in that example. So the
current parser won't handle that example currently. But this leaves the
possibility for expansion.
Sponsored-by: Joshua Antonishen on Patreon
The UUID is included in the GITMANIFEST in order to allow a single
key/value store to be used to store several special remotes, without any
namespacing. In that situation though, if the same ref is pushed to two
special remotes, it will result in git bundles with the same content.
Which is ok, until a re-push happens to one of the special remote.
At that point, the old git bundle will be deleted. That will prevent
fetching it from the other special remote, where the re-push has not
happened.
Adding the UUID avoids this problem.
And document remote.<name>.git-remote-annex-max-bundles which will
configure it.
datalad-annex uses a similar url format, but with some enhancements.
See https://github.com/datalad/datalad-next/blob/main/datalad_next/gitremotes/datalad_annex.py
I added the UUID to the URL, because it is needed in order to pick out which
manifest file to use. The design allows for a single key/value store to have
several special remotes all stored in it, and so the manifest includes
the UUID in its name.
While datalad-annex allows datalad-annex::<url>?, and allows referencing
peices of the url in the parameters, needing the UUID prevents
git-remote-annex from supporting that syntax. And anyway, it is a
complication and I want to keep things simple for now.
Sponsored-by: unqueued on Patreon
Added to git-annex_proxies todo because this is something OpenNeuro
would need in order to use the git-annex proxy.
Sponsored-by: Dartmouth College's OpenNeuro project
