Fixes reversion in 8.20200617 that made annex.pidlock being enabled result
in some commands stalling, particularly those needing to autoinit.
Renamed runsGitAnnexChildProcess to make clearer where it should be
used.
Arguably, it would be better to have a way to make any process git-annex
runs have the env var set. But then it would need to take the pid lock
when running any and all processes, and that would be a problem when
git-annex runs two processes concurrently. So, I'm left doing it ad-hoc
in places where git-annex really does run a child process, directly
or indirectly via a particular git command.
addurl: Fix reversion in 7.20190322 that made --file not be honored when
youtube-dl was used to download media.
8758f9c561 was on the right track, but missed that | otherwise prevented
the code it added from being used.
Also, refactored out a common function.
This commit was sponsored by Graham Spencer on Patreon.
I'm sure this used to work, but somewhere along the line something or
things (getCost and getAvailability I think, probably others)
started catching the exception and not displaying it. So, show warnings.
TVars were not updated atomically, which was ok when each thread got its
own External that was the only thing using these TVars. But, with the
async extension, several External instances can share the same var, so
it needs to be a TMVar to avoid read/write conflicts.
In particular, this makes PREPARE only be sent once.
Moving jobid generation to the git-annex side lets it be simplified a
lot.
Note that it will also be possible to generate one jobid per connection,
rather than a new job per request. That will make overflow not an issue,
and will avoid some work, and will simplify some of the code.
