requiredContentMap does not exclude dead repos. Usually this is not a
problem because it is used when we are operating on a repository, and in
that case, the repository is not dead (or if it is, the required content
configurations should still be used). But in the case of fsck, this made a
old required content config for a dead repository be warned about in a
situation where it is not a problem.
If an input file has been lost from all repositories, it is no longer
possible to compute the output. This will avoid dropping content that
was computed in such a situation, as well as making git-annex fsck --from
the compute remote do its usual thing when content has gone missing.
This implementation avoids recursing forever if there is a cycle,
which should not be possible anyway.
Note the use of RemoteStateHandle as a constructor here suggests that
this may not handle sameas remotes right, since usually a
RemoteStateHandle is constructed using the sameas uuid for a sameas
remote. That assumes a compute remote can even have or be a sameas remote.
Which doesn't seem to make sense, so I have not thought through what might
happen here in detail.
If it did, recompute would need to somehow support recomputing
non-annexed files.
And, annex.smallfiles is typically used for configuration files or
source code kind of things, where the user doesn't want it to be an
annexed file. Computed artifacts are not likely that kind of thing.
Also, git-annex importfeed is an example of something that does support
annex.addunlocked, but does not support annex.smallfiles.
