Error information shows "update your build to use at least one Scala compiler option like -Ywarn-unused", but it is already enabled in maven

[tribbloid]

I'm using the command line launch:

$ scalafix --verbose
warning: Name RemoveUnusedImports is deprecated. Use RemoveUnused instead (since 0.6.0)
warning: Name RemoveUnusedTerms is deprecated. Use RemoveUnused instead (since 0.6.0)
error: 2 errors
[E0] The Scala compiler option "-Ywarn-unused" is required to use RemoveUnused.
To fix this problem, update your build to use at least one Scala compiler
option like -Ywarn-unused, -Xlint:unused (2.12.2 or above), or -Wunused (2.13 only)
[E1] The Scala compiler option "-Ywarn-unused" is required to use RemoveUnused.
To fix this problem, update your build to use at least one Scala compiler
option like -Ywarn-unused, -Xlint:unused (2.12.2 or above), or -Wunused (2.13 only)

But -Ywarn-unused is already enabled in maven. Is there an option to correctly identify it?

[bjaglin]

All the scalac options used to compile sources must be passed as arguments when using the CLI (see --scalac-options in https://scalacenter.github.io/scalafix/docs/users/installation.html#help). Partly to check the setup and partly because it is needed (to know the semanticdb locations for example).

Since this can be a hassle, you can try https://github.com/evis/scalafix-maven-plugin if you use maven as build tool. It is a community plugin that allows you to automatically setup scalafix.

[tribbloid]

that may not be possible, the semanticDB plugin was known to cause problem in our project, but it has to be enabled for a key feature of scalafix we use (optimise imports)

Is there a way to inline it or optimise imports without semanticDB?

[bjaglin]

Semantic rules require semanticdb to run. You can reorganize/sort imports using https://github.com/NeQuissimus/sort-imports or even https://scalameta.org/scalafmt/docs/configuration.html#imports-expand, but semantic information is mandatory if you want more advanced behavior (https://scalacenter.github.io/scalafix/docs/rules/RemoveUnused.html or https://github.com/liancheng/scalafix-organize-imports).

What issue did you face with the semanticdb plugin?

[bjaglin]

Let's follow up on https://github.com/scalameta/scalameta since scalafix works as intended here