How to "re-run with -deprecation for details" in sbt?

Question

When I compile Scala code, by running sbt compile, SBT says:

$ sbt compile
...
[warn] there were 5 deprecation warnings; re-run with -deprecation for details
...

How do I do that? (From within SBT?)

Cajolery

Similar question (that includes the answer to your question) at #9416462 – Guano

Answer 1

sbt shell

While in sbt shell (if you don't want to change your build.sbt):

$ sbt
> set ThisBuild/scalacOptions ++= Seq("-unchecked", "-deprecation")
> compile
> exit

Due to in ThisBuild, set applies the settings to all sub-projects, as well.

Command Line

You could also run the above as a single command on command line.

sbt '; set ThisBuild/scalacOptions ++= Seq("-unchecked", "-deprecation") ; compile' 

The trick is to use ; (semicolons) to separate commands and ' (ticks) to include all ;-separated commands as a single argument to sbt.

sbt < 1.x

Instead of ThisBuild/scalacOptions use scalacOptions in ThisBuild

Pituri

@retronym: in Global instead of in ThisBuild also works equally well with subprojects—but why is the latter preferred? or is it even? – Melva

Answer 2

scalacOptions := Seq("-unchecked", "-deprecation")

Add this setting to your build.sbt, and, if you have a multi-module project, add it to every project's settings.

Peracid

Answer 3

As times flows new solutions are emerged. So, now you could re-run the scala compiler without issuing entire project rebuild.

You need to install ensime-sbt plugin:

addSbtPlugin("org.ensime" % "sbt-ensime" % "1.0.0")

After that you could use the ensimeCompileOnly task to compile single file. SBT allows per tasks settings configuration, so you could change for that tasks only:

set scalacOptions in (Compile, EnsimeKeys.ensimeCompileOnly) += "-deprecation"
ensimeCompileOnly src/main/scala/MyFile.scala

Dockyard

Adding Ensime just to get -deprecation is a terrible idea. Ensime is for supporting on-the-fly annotation in editors. Besides which, Ensime itself has a host of problems with some kinds of projects (most notably those that use macros heavily). – Sherer

ensime plugin is a small companion to the fat language server. You could use it separately. Or could just copy some functionality from it. – Dockyard