Summary:
We're seeing deadlocks where if the process forks (like in a update
worker) while a background python thread is holding the progress lock, it can
cause a deadlock in the forked process if the thread ever tries to access the
progress bar.
To fix it, let's invalidate the engine if the process forks.
Reviewed By: xavierd
Differential Revision: D21415152
fbshipit-source-id: 75607dd2c1ed122b3a9df68d359ba9dcdde78a77
Summary:
In preparation for merging fb-mercurial sources to the Eden repository,
move everything from the top-level directory into an `eden/scm`
subdirectory.
