scala_toolchain.md

scala_toolchain

scala_toolchain allows you to define global configuration to all Scala targets.

Some scala_toolchain must be registered!

Several options to configure scala_toolchain:

A) Use the default scala_toolchain:

In your workspace file add the following lines:

# WORKSPACE
# register default scala toolchain
load("@io_bazel_rules_scala//scala:toolchains.bzl", "scala_register_toolchains")
scala_register_toolchains()

B) Defining your own scala_toolchain requires 2 steps:

1. Add your own definition of scala_toolchain to a BUILD file:

   # //toolchains/BUILD
   load("@io_bazel_rules_scala//scala:scala_toolchain.bzl", "scala_toolchain")
   
   scala_toolchain(
       name = "my_toolchain_impl",
       scalacopts = ["-Ywarn-unused"],
       unused_dependency_checker_mode = "off",
       visibility = ["//visibility:public"]
   )
   
   toolchain(
       name = "my_scala_toolchain",
       toolchain_type = "@io_bazel_rules_scala//scala:toolchain_type",
       toolchain = "my_toolchain_impl",
       visibility = ["//visibility:public"]
   )

2. Register your custom toolchain from WORKSPACE:

   # WORKSPACE
   register_toolchains("//toolchains:my_scala_toolchain")

Attributes
scalacopts	List of strings; optional Extra compiler options for this binary to be passed to scalac.
scalac_jvm_flags	List of strings; optional List of JVM flags to be passed to scalac. For example ["-Xmx5G"] could be passed to control memory usage of Scalac. This is overridden by the scalac_jvm_flags attribute on individual targets.
scala_test_jvm_flags	List of strings; optional List of JVM flags to be passed to the ScalaTest runner. For example ["-Xmx5G"] could be passed to control memory usage of the ScalaTest runner. This is overridden by the jvm_flags attribute on individual targets.
unused_dependency_checker_mode	String; optional Enable unused dependency checking (see Unused dependency checking). Possible values are: off, warn and error.
enable_code_coverage_aspect	"on" or "off"; optional; defaults to "off" This enables instrumenting tests with jacoco code coverage.