Here is a helpful checklist to go through before uploading change lists (CLs) on Gerrit. This checklist is designed to be streamlined. See contributing to Chromium for a more thorough reference.
You should create a new branch before starting any development work. It's helpful to branch early and to branch often in Git.
git new-branch <branch_name>
which is equivalent to
git checkout -b <branch_name> --track origin/master
Do your thing. There's no further advice here about how to write or fix code.
After making your changes, check that common targets build correctly:
It‘s easy to inadvertently break one of the other builds you’re not currently working on without realizing it. Even though the Commit Queue should catch any build errors, checking locally first can save you some time since the CQ Dry Run can take a while.
Make sure you hit every code path you changed.
Consider automating any manual testing you did in the previous step.
Run git cl format --js. The --js option also formats JavaScript changes.
Run git upstream-diff to check over all of the changes you've made from the most recent checkpoint on the remote repository.
Run git add <path_to_file> for all of the relevant files you've modified.
Run git commit. Here are some tips for writing good commit messages.
If you have many commits on your current branch, and you want to avoid some nasty commit-by-commit merge conflicts in the next step, it is recommended to squash your commits into a single commit. This is done by running git rebase -i origin/master. You should see a list of commits, each commit starting with the word “pick”. Make sure the first commit says “pick” and change the rest from “pick” to “squash”. This will squash each commit into the previous commit, which will continue until each commit is squashed into the first commit.
Run git rebase-update. This command updates all of your local branches with remote changes that have landed since you started development work, which could've been a while ago. It also deletes any branches that match the remote repository, such as after the CL associated with that branch had merged. You may run into rebase conflicts which should be manually fixed before proceeding with git rebase --continue. Rebasing prevents unintended changes from creeping into your CL.
Note that rebasing has the potential to break your build, so you might want to try re-building afterwards.
Run git cl upload. Some useful options include:
--cq-dry-run (or -d) will set the patchset to do a CQ Dry Run.-r <chromium_username> will add reviewers.-b <bug_number> automatically populates the bug reference line of the commit message.Run git cl web to go to the Gerrit URL associated with the current branch. Open the latest patch set and verify that all of the uploaded files are correct. Click Expand All to check over all of the individual line-by-line changes again.
Click CQ Dry Run. Fix any errors because otherwise the CL won't pass the commit queue (CQ) checks. Consider waiting for the CQ Dry Run to pass before notifying your reviewers, in case the results require major changes in your CL.
Click Find Owners or run git cl owners to find file owners to review your code and instruct them about which parts you want them to focus on. Add anyone else you think should review your code. For your CL to land, you need an approval from an owner for each file you‘ve changed, unless you are an owner of some files, in which case you don’t need separate owner approval for those files.
Then go through this commit checklist again. Reply to all comments from the reviewers on Gerrit and mark all resolved issues as resolved (clicking Done or Ack will do this automatically). Click Reply to ensure that your reviewers receive a notification. Doing this signals that your CL is ready for review again, since the assumption is that your CL is not ready for review until you hit reply.
Once you have obtained a Looks Good To Me (LGTM), which is reflected by a Code-Review+1 in Gerrit, from at least one owner for each file, then you have the minimum prerequisite to land your changes. It may be helpful to wait for all of your reviewers to approve your changes as well, even if they're not owners. Click Submit to CQ to try your change in the commit queue (CQ), which will land it if successful.
After your CL is landed, you can use git rebase-update or git cl archive to clean up your local branches.