Apache Cassandra doesn't use GitHub pull requests as part of the development process. In fact, this repository is a GitHub mirror of the official repo.
Use Cassandra JIRA to create an issue, then either attach a patch or post a link to a GitHub branch with your changes.
- How you can contribute to Apache Cassandra presentation by Yuki Morishita
- Code style wiki page
- Running Cassandra in IDEA guide
- Running Cassandra in Eclipse guide
- Cassandra Cluster Manager - CCM and a guide blog post
- Cassandra Distributed Tests aka dtests
- Cassandra Testing Guidelines - see TESTING.md