gerrit rebase review branch on latest changes from upstream branch

Question

Is it possible to rebase topic branch with some changes pending review on upstream? I want to preserve all review comments, etc. but also have latest changes made in upstream.

I thought about following workflow (not sure if it works):

• rebase local topic branch on latest changes from upstream;
• force push new commits in local topic branch (without commits pushed to gerrit for review) to gerrit's refs/heads/thetopicbranch in order to replace commits in gerrit's branch with new changes from upstream;
• push local topic branch head to gerrit for review, ie HEAD:refs/for/thetopicbranch - this will push changes that needs review and gerrit (I hope) match that commits with already pushed by their Change-Id.

The same, but in git commands (everything is done on local topic branch):

• git rebase upstream
• git push gerrit:project `git merge-base upstream localtopicbranch`:refs/heads/thetopicbranch -f
• git push gerrit:project HEAD:refs/for/thetopicbranch

Will this schema work?

Answer 1

Sure it is fairly easy to put some topic branch changes on top of other upstream changes which are pending in Gerrit. The workflow I typically use:

• Download the upstream changes you want as a parent. You typically don't want to create a new patchset for these changes, so I use the 'git checkout' command which can be copy-pasted from Gerrit. With the other commands (pull and cherry-pick), you will create a new commit if there has been other development since the upstream change was uploaded.
• Cherry-pick the change you want to be on top of the upstream change(s) you just pulled down. Copy-paste the git cherry-pick command from gerrit
• Upload to gerrit via git push <server> HEAD:refs/for/<topicBranch>