Store initial repo state in the merger
When we ask a merger to speculatively merge changes, record the
complete starting state of each repo (defined as all of the refs
other than Zuul refs) and return that at the completion of all
of the merges.
This will later be used so that when a pipeline manager asks a
merger to speculatively merge a change, the process can later
be repeated by the (potentially multiple) executors which will
end up running jobs for the change. Between the time that the
merger runs and the jobs run, the underlying repos may have changed.
This ensures a consistent state throughout.
The facility which used saved zuul refs within the merger repo
to short-cut the merge sequence for an additional change added to
a previously completed merge sequence is removed, because in that
case, we would not be able to know the original repo state for the
earlier merge sequence. This is slightly less efficient, however,
we are proposing removing zuul refs anyway due to the maintenance
burden they cause.
Change-Id: If0215d53c3b08877ded7276955a55fc5e617b244
5 files changed