push: add a way to allow concurrent pushes on unrelated heads...
push: add a way to allow concurrent pushes on unrelated heads
Client has a mechanism for the server to check that nothing changed server side
since the client prepared a push. That check is wide and any head changed on
the server will lead to an aborted push. We introduce a way for the client to
send a less strict checking. That logic will check that no heads impacted by
the push have been affected. If other unrelated heads (including named branches
heads) have been affected, the push will proceed.
This is very helpful for repositories with high developers traffic on different
heads, a common setup.
That behavior is currently controlled by an experimental option. The config
should live in the "server" section but bike-shedding of the name will happen
in the next changesets. Servers advertise this capability through a new bundle2
capability 'checkeads', using the value 'related'.
The 'test-push-race.t' is updated to check that new capabilities on the
documented cases.
