Different compile options for tests and release in SBT? - sbt

Question

I have a project where I need to disable assertions when creating the binaries. Now I could just do:
scalacOptions += "-Xdisable-assertions"
But then also the unit tests would be run without assertions. Is there a (hopefully) simple way to achieve what I need?

Answer 1

How do you create the binaries? What task/command do you use?
Use the task as the scope for scalacOptions to have different values for them. See Scoping by configuration axis:
By default, all the keys associated with compiling, packaging, and
running are scoped to a configuration and therefore may work
differently in each configuration. The most obvious examples are the
task keys compile, package, and run; but all the keys which affect
those keys (such as sourceDirectories or scalacOptions or
fullClasspath) are also scoped to the configuration.
Use inspect when in doubt.
> inspect scalacOptions
[info] Task: scala.collection.Seq[java.lang.String]
[info] Description:
[info] Options for the Scala compiler.
[info] Provided by:
[info] {file:/C:/dev/sandbox/task-dependsOn/}task-dependson/compile:scalacOptions
[info] Defined at:
[info] (sbt.Classpaths) Defaults.scala:1424
[info] Dependencies:
[info] task-dependson/compile:autoCompilerPlugins
[info] task-dependson/compile:settingsData
[info] task-dependson/compile:update
[info] task-dependson/compile:buildDependencies
[info] task-dependson/compile:thisProjectRef
[info] Delegates:
[info] task-dependson/compile:scalacOptions
[info] task-dependson/*:scalacOptions
[info] {.}/compile:scalacOptions
[info] {.}/*:scalacOptions
[info] */compile:scalacOptions
[info] */*:scalacOptions
[info] Related:
[info] b/compile:scalacOptions
[info] b/test:scalacOptions
[info] task-dependson/test:scalacOptions
[info] task-dependson/jacoco:scalacOptions
[info] a/jacoco:scalacOptions
[info] */*:scalacOptions
[info] a/test:scalacOptions
[info] a/compile:scalacOptions
[info] b/jacoco:scalacOptions
The Compile configuration scope is the default one (see show defaultConfiguration for a project) so scalacOptions += "-Xdisable-assertions" is in fact scalacOptions in Compile += "-Xdisable-assertions". Use different configuration, say Test, and you'll get different results.
There's however a hitch in SBT (I missed the very first time I responded) - settings are chained and when a setting is not defined in a scope, it gets its value from a more general scope. When I said, scalacOptions +=... is in fact scalacOptions in Compile I missed the important feature of settings - scalacOptions is global while scalacOptions in Compile is Compile-scoped.