export, sync --content: Avoid unnecessarily trying to upload files to an
exporttree remote that already contains the files.
When the export was origianly made in one repo and now git-annex is
running in a different repo, the export database is not yet populated with
information about the exportLocation of files. So, it was trying to upload
the files to the export, even when it already contained them.
sync --content would first download the content from the export, and then
re-upload the content back.
And this also led to "not available" failures for each file that was not
locally present yet.
Fix: Just use checkPresentExport before uploading; if it succeeds update
the database.
This is a surprising oversight, it's possible it fixes a reversion because
I would have thought I'd have noticed this problem when originally
developing exporttree remotes.
This commit was sponsored by Jochen Bartl on Patreon.
When an export conflict prevents accessing a special remote, be clearer
about what the problem is and how to resolve it.
This commit was sponsored by Trenton Cronholm on Patreon.
Don't much like that there's no way to distinguish between having the whole
content and having an old version of the file that's bigger, but of course
resuming a http transfer can always yield the wrong result if the file on
the http server is changing, and git-annex will detect that when it
verifies the downloaded content.
This work is supported by the NIH-funded NICEMAN (ReproNim TR&D3) project.
