Out of the box behaviours

When adding kantan.sbt as a plugin to your build, you will get a few new behaviours immediately.

Scalac

Scalac will now use a fair amount of compiler flags.

The majority of them are additional checks and warnings - the default scalac behaviour being far too permissive for my tastes. These go from unused imports to shadowing of function parameters. If you’re into this type of things, see the StrictPlugin for more aggressive options.

A few standard language features will also be enabled by default - macros, existentials, higher-kinded types… because I feel they really should be part of the standard language rather than locked away behind weird imports.

Headers

All my code, either OSS or not, falls under some form of license. My OSS work is mostly Apache, for example.

I like to include this in a header in all of my sources. sbt-header is the perfect tool for this, and is enabled by default.

Note that, due to the way sbt-header works, there is no trivial way to automate header generation by default - the standard pattern is to manually enable AutomateHeaderPlugin for each project. There is, however, a (rather nasty) trick to achieve this. Have a look at KantanAutomateHeaderPlugin if you’re interested in this.

Finally, if sbt-boilerplate is enabled for one of your projects, template files will also have generated headers.

Doctest

sbt-doctest is a really neat project that lets you write sample code in your documentation and turn that code into tests. A fairly common pattern I’ve started using is, when done with a bit of code, to start a REPL and manually test a couple of things. If they work out, paste them in the documentation - free documentation and simple tests for free! This, of course, does not replace proper unit tests, but at the very least guarantees that your documentation’s samples are always up to date.

kantan.sbt enables sbt-doctest, with a few default configuration options. At the time of writing:

doctestMarkdownEnabled := true
doctestTestFramework := DoctestTestFramework.ScalaTest

These can of course be overriden in your own buildfiles.

Validation

kantan.sbt declares a validate command that will run all tests, check code style, generate all documentation, and write a coverage report. The basic purpose of this is to be executed during CI.

Note that style checking is documented here