migrate: Support adding size to URL keys that were added with --relaxed, by
running eg: git-annex migrate --backend=URL foo
Since url keys cannot be generated, that used to fail. Make it notice that
the backend is not changed, and just get the size of the content.
Sponsored-by: Brock Spratlen on Patreon
pull, sync: When operating on content, automatically hard link objects
that have been migrated.
Added annex.syncmigrations config that can be set to false to prevent
pull and sync from migrating object content.
I think that true is a good default for this config, because it avoids
users having to re-download migrated content or learning about migration.
But, some users will surely not like it, whether because it does take some
time (especially for the first git-annex branch scan when there is a long
history), or because they want to deal with it manually, or because their
filesystem doesn't support hard links and they don't want it to copy
objects.
Sponsored-by: k0ld on Patreon
And avoid migrate --update/--aply migrating when the new key was already
present in the repository, and got dropped. Luckily, the location log
allows distinguishing from the new key never having been present!
That is mostly useful for --apply because otherwise dropped files would
keep coming back until the old objects were reaped as unused. But it
seemed to make sense to also do it for --update. for consistency in edge
cases if nothing else. One case where --update can use it is when one
branch got migrated earlier, and we dropped the file, and now another
branch has migrated the same file.
Sponsored-by: Jack Hill on Patreon
This only avoids extra work and a warning messsage. It seems likely that
in such a situation, the user does not want migrations to insecure
hashes, and so best to ignore them as much as possible. If
the user merges a branch that switches annexed files to an insecure
hash, they will notice that the file contents are unavailable,
and git-annex get will tell them the problem then. So it does not seem
useful to have migrate --update also complain about it.
Could use some more testing.
When the old key is not present, Command.ReKey.linkKey' will return
False, so this handles that case ok.
But, I do wonder if distributed migration may need to deal with the old
key getting copied into the repository later. In that situation,
re-running migrate --update won't link it to the new key. It may be that
some users will need that. They can delete .git/annex/migrate.log and
run it again, but that is not a good user interface. Maybe either have
a way to re-run all distributed migrations, or record migrations
in a database and scan the db to find migrations to do in a future run?
Sponsored-by: Kevin Mueller on Patreon
The git log is outputting the diff, but this only looks at the new
files. When we have a new file, we can get the old filename by just
replacing "new" with "old". And then use branchFileRef to refer to it
allows catting the old key.
While this does have to skip past the old files in the diff, it's still
faster than calling git diff separately.
Sponsored-by: Nicholas Golder-Manning on Patreon
This is most of the way there, but not quite working.
The layout of migrate.tree/ needs to be changed to follow this approach.
git log will list all the files in tree order, so the new layout needs
to alternate old and new keys. Can that be done? git may not document
tree order, or may not preserve it here.
Alternatively, change to using git log --format=raw and extract
the tree header from that, then use
git diff --raw $tree:migrate.tree/old $tree:migrate.tree/new
That will be a little more expensive, but only when there are lots of
migrations.
Sponsored-by: Joshua Antonishen on Patreon
This will allow distributed migration: Start a migration in one clone of
a repo, and then update other clones.
commitMigration is a bit of a bear.. There is some inversion of control
that needs some TMVars. Also streamLogFile's finalizer does not handle
recording the trees, so an interrupt at just the wrong time can cause
migration.log to be emptied but the git-annex branch not updated.
Sponsored-by: Graham Spencer on Patreon
