# How to contribute

## Single-change commits and pull requests

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.

## Contributor license agreement (CLA)

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.