Race condition in CI
Right after a push, if the runner is fast, we get regular cases of the job not being able to grab the changeset that has been pushed.
This is presumably because we push to the inner Git repository in a pre-transaction hook, and that fires Git's post-receive
hook before the Mercurial transaction has committed.
This might also be the reason for #66 (closed).
Fixing this goes along the lines of #73 (closed), and that's too much of a change for the 0.6 series (current stable).