Added remote.name.annex-speculate-present config that can be used to
make cache remotes.
Implemented it in Remote.keyPossibilities, which is used by the
get/move/copy/mirror commands, and nothing else. This way, things like
whereis will not show content that's speculatively present.
The assistant and sync --content were not using Remote.keyPossibilities,
and were changed to use it.
The efficiency hit should be small; Remote.keyPossibilities is only
used before transferring a file, which is the expensive operation.
And, it's only doing one lookup of the remoteList and a very cheap
filter over it.
Note that, git-annex still updates the location log when copying content
to a remote with annex-speculate-present set. In this case, the location
tracking will indicate that content is present in the remote. This may
not be wanted for caches, or may not be a real problem for them. TBD.
This commit was supported by the NSF-funded DataLad project.
git-annex allows managing files with git, without checking the file
contents into git. While that may seem paradoxical, it is useful when
dealing with files larger than git can currently easily handle, whether due
to limitations in memory, checksumming time, or disk space.
For documentation, see doc/ or <https://git-annex.branchable.com/>
fd5a392006