versions

org.hammerlab.sbt:versions

addSbtPlugin("org.hammerlab.sbt" % "versions" % "5.0.0")

SBT plugin for setting and managing dependencies' versions; source.

v: set snapshot version

Set the current project's version with a variety of short-hands:

// Set the version to "1.2.3-SNAPSHOT", or "1.2.3" if "snapshot" is true
v"1.2.3"
v("1.2.3")

// un-snapshot the versions set above
snapshot := false

These work by setting the revision key, which then propagates to the version key.

r: fix "released" version, disable publishing

The r ("release") syntax sets the version, presumably to an already-released value, and disables publish tasks:

r"1.2.3"

This is useful if you want to publish some modules in a project that depend on other modules in the same project that you don't want to publish.

Workflow: releasing some modules, not others

I use a command alias prep in my ~/.sbt/1.0/settings.sbt to set prepare all non-r"…" modules for release:

addCommandAlias("prep", "set snapshot in ThisBuild := false")

• this un-snapshots all v"…" modules, which are now eligible for release
• r"…" modules can be depended on by them, but will not be released themselves.

Then, to perform a release of certain modules in a project:

• set the desired modules' release versions using v"…"
• fix all other modules' versions with r"…"
• in the SBT repl:

  prep
  +publishSigned
  sonatypeClose
  sonatypeRelease

Default Versions

The defaultVersions setting, and versions() helper, allow for setting versions for dependencies that may be used more than once in a project.

For example, a plugin can define {group,artifact} coordinates for common dependencies:

object MyPlugin extends AutoPlugin {
  object autoImport {
    val     guava = "com.google.guava" ^ "gauva"
    val scalatest = "org.scalatest" ^^ "scalatest"
  }
}

(cf. the parent module in this repo)

Then a downstream, multi-module project can just specify the versions for such dependencies:

default(
  versions(
        guava → "19.0",
    scalatest → "3.0.0"
  )
)

lazy val module1 = project.settings(dep(guava))
lazy val module2 = project.settings(dep(scalatest tests))

// override defaults
lazy val module3 = project.settings(
  dep(
    guava % "16.0.1",
    scalatest % "3.0.4" tests
  )
)

hammerlab/spark-bam provides an example of this pattern, and the parent plugin in this repo provides many common dependency-aliases, including the two above.

Dependency-group alias DSL

Many shorthands for defining aliases and settings for groups of related dependencies.

Here's an example from parent:

object circe
  extends Libs(
    // this is a template for Maven coordinates of the modules defined with `lib` below
    "io.circe" ^^ "circe" ^ "0.9.3"
  ) {
  val    core = lib
  val generic = lib
  val literal = lib
  val  parser = lib
}

This enables depending on various circe modules via:

dep(
  // alias for circe.core, since it was the first declared `lib` above
  circe,
  circe.generic
)

Their (shared) version is also given its own setting:

versions(
  circe → "0.9.2"
)

// equivalent
circe.version = "0.9.2"

You can override the settings member of a Libs group like the above; here's an example from spark:

object spark
  extends Libs(
    ("org.apache.spark" ^^ "spark" ^ "2.2.1") - scalatest
  ) {

  val   core = lib
  val graphx = lib
  val  mllib = lib
  val    sql = lib

  /**
   * Add Spark dependencies and set the Scala version to 2.11.x
   */
  override val settings: SettingsDefinition =
    `2.11`.only ++
    Seq(
      Deps.dep(
        spark.core provided,
        spark.tests tests,
        hadoop provided,
        kryo
      ),

      // This trans-dep creates a mess in Spark+Hadoop land; just exclude it everywhere by default.
      excludeDependencies += ExclusionRule("javax.servlet", "servlet-api")
    )
}

This allows a top-level build.sbt declaration:

spark

That adds the specified settings (see spark for more discussion; note also the scalatest exclusion in the coordinate-template, as another option).

Many plugins in thie repo use this DSL in interesting ways; feel free to explore!