Gerrit workflow

Merging straight to master

If you want to make a change that you want to merge with master, the best way is to first create a topic branch

git checkout -b foo

make a single commit with your feature

git commit -m "Made the thing X finally work"

and push that branch to review via

git push origin foo:refs/for/master/foo

Avoid working directly on master, as you will have problems resolving conflicts if someone else pushed to master before you. If you have your work on a separate branch, then resolving conflicts is as simple as

git checkout master
git pull origin master
git checkout foo
git rebase master
git push origin foo:refs/for/master/foo

Use rebase instead of merge

Because of how gerrit relies on change-ids, in order to resolve conflicts (pull changes to your topic branch) the best practice is to rebase topic branch onto master/other branch you want to push to. This way you preserve the change-id without having to ammend the merge commit. For example if you submit foo to refs/for/master with history as follows:

      a < foo
     /
 ---s < master

Then gerrit will create a change with change-id taken from the commit a. But say after you passed review but before you submitted to master someone submitted their change:

      a < foo
     /
 ---s---x < master

If you rebase foo onto master you’ll have

          a < foo
         /
 ---s---x < master

And you can easily push a again with the same change-id.

Working on a feature branch

As mentioned in the other example, you should use rebase instead of merge. But if you’re working on a feature branch with your team then you’ll run into the problem of pulling rewritten history. So the best way to work on a feature branch foo is to locally create tracking branch foo that you use only for pulling others’ changes and create one more branch e.g. dev_foo that you use only for pushing. Then use the basic workflow as if foo was master and dev_foo your topic branch.

For example your history might look like this before submitting a change to review

           x < dev_foo
          /
     a---b < foo
    /
---s---t---u < master

To push commit x to review and have it submitted to foo use

git push origin dev_foo:refs/for/foo/dev_foo