External special remotes will refuse to operate on keys with spaces in
their names. That has never worked correctly due to the design of the
external special remote protocol. Display an error message suggesting
migration.
Not super happy with this, but it's a pragmatic solution. Better than
complicating the external special remote interface and all external special
remotes.
Note that I only made it use SafeKey in Request, not Response. git-annex
does not construct a Response, so that would not add any safety. And
presumably, if git-annex avoids feeding any such keys to an external
special remote, it will never have a reason to make a Response using such a
key. If it did, it would result in a protocol error anyway.
There's still a Serializeable instance for Key; it's used by P2P.Protocol.
There, the Key is always in the final position, so it's ok if it contains
spaces.
Note that the protocol documentation has been fixed to say that the File
may contain spaces. One way that can happen, even though the Key can't,
is when using direct mode, and the work tree filename contains spaces.
When sending such a file to the external special remote the worktree
filename is used.
This commit was sponsored by Thom May on Patreon.
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/>
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