Importing from a special remote honors its preferred content too; unwanted
files are not imported. But, some preferred content expressions can't be
checked before files are imported, and trying to import with such an
expression will fail.
Tested this with scenarios including changing the preferred content
expression and making sure merging the import didn't delete files that were
no longer wanted.
There was one minor inefficiency mentioned in the todo that I punted on.
Make the import have the previous import as a parent, so eg `git log --stat`
displays a useful diff.
Also a minor optimisation, only calculate the depth of the imported history
once.
Prevents merging the import from deleting the non-preferred files from
the branch it's merged into.
adjustTree previously appended the new list of items to the old, which
could result in it generating a tree with multiple files with the same
name. That is not good and confuses some parts of git. Gave it a
function to resolve such conflicts.
That allowed dealing with the problem of what happens when the import
contains some files (or subtrees) with the same name as files that were
filtered out of the export. The files from the import win.
This includes a note about how include= and exclude= match when exporting
a subtree. I don't know if the note is prominent enough, but the
behavior seems unsurprising enough.
This will let import try to match preferred content expressions before
downloading the content and generating its key.
If an expression needs a key, it preferredContentParser with
preferredContentKeylessTokens will fail to parse it.
standard and groupwanted are not in preferredContentKeylessTokens
because they may refer to an expression that refers to a key.
That needs further work to support them.
Added the ability to run one job per CPU (core), by setting annex.jobs=cpus,
or using option --jobs=cpus or -Jcpus.
Built with future expansion in mind, including not defaulting matching on
Concurrency so more constructors can later be added, and using "cpu"
instead of "0".
This way no history is lost, neither what was exported to the remote,
or the history of changes that is imported from it. No complicated
correlation of two possibly very different histories is needed, just
record what we know and then git merge will do a good job.
Also, it notices when the remote tracking branch doesn't need to be updated,
and avoids doing anything, so noop remotes are super cheap.
The only catch here is that, since the commits generated for imports
from the remote don't have a stable date or author/committer, each
(non-noop) import generates different commits for the same imported
trees. So, when the imported remote tracking branch is merged into master
and then a change is imported again, there will be an extra series of
commits, which will get more and more expensive each time.
This seems to call for making stable commits for imports. Also that
seems a good idea to make importing in several repositories have the
same result.
