Scalastyle - SBT plugin

Overview

This project is intended to provide Scala 2.11/2.12/2.13 & SBT 1.x plugin support for Scalastyle.

Repository

The repository for the Scalastyle SBT plugin is: https://oss.sonatype.org/content/repositories/releases/com/beautiful-scala

Setup

Add the following line to project/plugins.sbt

addSbtPlugin("com.beautiful-scala" % "sbt-scalastyle" % "1.5.1")

Usage

You will need a configuration file. The easiest way to get one is to use the scalastyleGenerateConfig command:

sbt scalastyleGenerateConfig

This will create a scalastyle-config.xml in the current directory, with the default settings. Then, you can check your code with the scalastyle command

sbt scalastyle

This produces a list of errors on the console, as well as an XML result file target/scalastyle-result.xml (CheckStyle compatible format).

Configuration options

If the remote source for your scalastyle-config.xml file is secured and requires the passing of tokens in the header of the http request or ssh authentication then scalastyleConfigUrl will not suffice. A work around is to define your own update task and make scalastyle depend on it in your build.sbt or Build.scala.

This example use enterprise github (private repositories) through the REST API v3, bitbucket API to get raw files is similar:

lazy val updateScalaStyle = taskKey[Unit]("updateScalaStyle")

updateScalaStyle := {
    /**
    * Create a security token under Github > Profile Settings > Application
    * add repo_org in the scope of that token
    * set it to environment variable SBT_GITHUB_TOKEN
    *
    * ex:
    * export SBT_GITHUB_TOKEN='1234567890abcdef1234567890abcdef'
    */
    sys.env.get("SBT_GITHUB_TOKEN") match {
    case Some(oauthToken) =>
        val configFileUrl = "https://raw.githubusercontent.com/[owner]/[repository]/[branch_or_commit]/[path]/scalastyle-config.xml"
        val result: Int = file("target/scalastyle-config.xml") #< s"curl --fail -u $oauthToken:x-oauth-basic $configFileUrl" !
    case None =>
        println("Please set system variable SBT_GITHUB_TOKEN to update scalastyle config file")
    }
}

(scalastyle in Compile) <<= (scalastyle in Compile) dependsOn updateScalaStyle

(scalastyle in Test) <<= (scalastyle in Test) dependsOn updateScalaStyle

NB: This uses curl so, while it works correctly on MacOS and Linux (or other *NIX) it might give problem on windows environments.

Running scalastyle on your test sources

You can check your test sources (scalaSources in Test) using the test:scalastyle command

sbt test:scalastyle

This has exactly the same output as the scalastyle command, except that the generated XML file is target/scalastyle-test-result.xml by default. All of the configuration options for the scalastyle command are available in the Test configuration for test:scalastyle, but you need to use the Test configuration. For instance:

(scalastyleConfig in Test) := baseDirectory.value / "scalastyle-test-config.xml"
(scalastyleConfig in Test) := file("/foo/bar/scalastyle-test-config.xml")
(scalastyleConfigUrl in Test) := Some(url("https://raw.githubusercontent.com/beautiful-scala/scalastyle/v1.5.1/src/main/resources/default_config.xml"))

Running scalastyle as part of another task

You can also have your scalastyle checks automatically run as part of another task:

// Create a default Scala style task to run with tests
lazy val testScalastyle = taskKey[Unit]("testScalastyle")

// scalastyle >= 0.9.0
testScalastyle := scalastyle.in(Test).toTask("").value
// scalastyle <= 0.8.0
testScalastyle := org.scalastyle.sbt.ScalastylePlugin.scalastyle.in(Test).toTask("").value

(test in Test) := ((test in Test) dependsOn testScalastyle).value

or as part of the compile task:

lazy val compileScalastyle = taskKey[Unit]("compileScalastyle")

// scalastyle >= 0.9.0
compileScalastyle := scalastyle.in(Compile).toTask("").value
// scalastyle <= 0.8.0
compileScalastyle := org.scalastyle.sbt.ScalastylePlugin.scalastyle.in(Compile).toTask("").value

(compile in Compile) := ((compile in Compile) dependsOn compileScalastyle).value

But note that this makes the compile task dependent on the scalastyle task - the scalastyle task executes first. This can cause problems because if the code doesn’t compile, you’ll get the scalastyle errors messages, not the scalac ones. Great though scalastyle is, it can’t match the error messages produced by the compiler. :-)