A git commit ought to be a self-contained, single change with a descriptive message. This helps with review and with identifying or reverting changes if issues are uncovered later on.
Pull requests typically comprise a single git commit. (In some cases, for
instance for large refactors or internal rewrites, they may contain several.)
In preparing a pull request for review, you may need to squash together
multiple commits. We ask that you do this prior to sending the PR for review if
possible. The git rebase -i command might be useful to this end.
Contributions to this project must be accompanied by a Contributor License Agreement. You (or your employer) retain the copyright to your contribution; this simply gives us permission to use and redistribute your contributions as part of the project. Head over to https://cla.developers.google.com/ to see your current agreements on file or to sign a new one.
You generally only need to submit a CLA once, so if you've already submitted one (even if it was for a different project), you probably don't need to do it again.