A warning message is unsatisfying. But erroring out is too hard a failure,
especially since it may well work fine if the user has enabled passwordless
ssh.
I did think about falling back to one ssh connection at a time in this
case, but it would have needed a rework of every ssh call, which
seems far overboard for such a niche problem. There's no single place where
git-annex runs ssh, so no one place that it could block a concurrent call
on a semaphore. And, even if it did fall back to one ssh connection at a
time, it seems to me that doing so without warning the user about the
problem just invites bug reports like "git-annex is ignoring my -J2 and
only doing one download at a time". So a warning is needed, and I suppose
is good enough.
If git-credential has it cached and does not prompt, this will
unfortunately result in a brief flicker, as the displayed console
regions are hidden while running it and then re-displayed. Better than a
corrupted display.
Actually, I tried it and don't see a visible flicker, so probably only
over a slow ssh will it be apparent.
using git credential to get the password
One thing this doesn't do is wrap the password prompting inside the prompt
action. So with -J, the output can be a bit garbled.
Rather than leaking the name of the temp file, just say the config parse
failed, and where the config was downloaded from.
Not closing the bug report because two issues were reported in the same
bug report, because the universe wants me to continually re-read old
unclosed bug reports to waste my time determining what still needs to be
done.