This is a small and simple contribution guide, every contribution is welcome if it is compliant with this guide.
- naming convension: see http://docs.scala-lang.org/style/naming-conventions.html
- indentation is done with 2 spaces
- comments are welcome not only when the code itself need furher explanations
- each function should have a test written using scala-test syntax, see samples in src/test
- Fixes the root cause of a bug in existing functionality
- Adds functionality or fixes a problem needed by a large number of users
- Simple, targeted
- Maintains or improves consistency
- Easily tested; has tests
- Reduces complexity and lines of code
- Change has already been discussed and is known to committers
- Band-aids a symptom of a bug only
- Introduces complex new functionality, especially an API that needs to be supported
- Adds complexity that only helps a niche use case
- Adds user-space functionality that does not need to be maintained in Spark, but could be hosted externally
- Changes a public API or semantics (rarely allowed)
- Adds large dependencies
- Changes versions of existing dependencies
- Adds a large amount of code
- Makes lots of modifications in one "big bang" change