Yesterday, Andrei brought to my attention that my attempt to merge
Sergey's PR [1] using the default merge strategy (create a merge commit)
on Github broke the linear history of the calcite repository.
I have since removed the commit and merged the PR using a rebase.
I have also tested the merge behaviors on a test repo on Github. The
"Rebase and merge" strategy will replicate what we are currently doing
using the git client to preserve linear history.
I have asked infra to disable the "create a merge commit" and "squash
merge" strategies [2] on all our repositories.
The merge button on Github should now be safe to use. In the event that
there is a conflict and Github is not able to perform the rebase,
committers should manually rebase the commit(s) and merge the PR using
the git client.
[1] https://github.com/apache/calcite/pull/772
[2] https://issues.apache.org/jira/browse/INFRA-17541
