This is to support, eg a borg repo as a special remote, which is
populated not by running git-annex commands, but by using borg. Then
git-annex sync lists the content of the remote, learns which files are
annex objects, and treats those as present in the remote.
So, most of the import machinery is reused, to a new purpose. While
normally importtree maintains a remote tracking branch, this does not,
because the files stored in the remote are annex object files, not
user-visible filenames. But, internally, a git tree is still generated,
of the files on the remote that are annex objects. This tree is used
by retrieveExportWithContentIdentifier, etc. As with other import/export
remotes, that the tree is recorded in the export log, and gets grafted
into the git-annex branch.
importKey changed to be able to return Nothing, to indicate when an
ImportLocation is not an annex object and so should be skipped from
being included in the tree.
It did not seem to make sense to have git-annex import do this, since
from the user's perspective, it's not like other imports. So only
git-annex sync does it.
Note that, git-annex sync does not yet download objects from such
remotes that are preferred content. importKeys is run with
content downloading disabled, to avoid getting the content of all
objects. Perhaps what's needed is for seekSyncContent to be run with these
remotes, but I don't know if it will just work (in particular, it needs
to avoid trying to transfer objects to them), so I skipped that for now.
(Untested and unused as of yet.)
This commit was sponsored by Jochen Bartl on Patreon.
Don't want to try to use these remotes as key/value remotes, which will
surely fail. It only recently became possible for importtree to be set
w/o exporttree, so before this code was ok.
(cherry picked from commit 97599cb0f7f4115aa5a3e81a91ee3d1d6c52dc84)
I think this could cause unnecessary changes to the git-annex branch,
and retrieveExportWithContentIdentifier is now also used for getting
content from importtree=yes remotes, so it would happen more frequently
so let's avoid.
This is better than using the equivilant actions for export remotes,
especially for getting content, since the ContentIdentifier checking
means we can be sure (enough) that the content is valid to not force
verification of content. Which allows getting keys of types that cannot
be verified.
Also, reorganized the internals of adjustExportImport which was becoming
very hard to follow. Now it's clear what each method does in each case.
Ah, it seemed too easy before when I was implementing importrree only,
and it was because all the key-based actions needed to be handled too.
Mostly copied from isexport, and this works. It does seem that
an import remote could use retrieveExportWithContentIdentifier
rather than retrieveExport, and checkPresentExportWithContentIdentifier
rather than checkPresentExport, which would both be more accurate.
Importtree only remotes are new; importtree remotes used to always also be
exporttree, so were untrusted.
Since an import remote is one that can be edited by something other than
git-annex, it's clearly not trustworthy at all.
In cd1676d604, it stopped using that to avoid surprising behavior
when the location log and remote content were out of sync.
But, it seems that may have changed some behavior users relied on as
well, and also Remote.hasKeyCheap should be faster than checking then
location log.
So, try Remote.hasKeyCheap first, and only if it does not have the key,
fall back to checking the location log. If the location log still thinks
it's present, go ahead and try to get it, so the user will see a failure
rather than silently skipping a file what whereis says is on the remote.
This does make slightly slower the case where the remote does not have
the key, and location log and Remote.hasKeyCheap agree, since it now
checks both. But only 1 stat slower.
