[error] bad option: -P:silencer:checkUnused in Compile / doc

[solarmosaic-kflorence]

Just wanted to note that adding this flag to scalacOptions caused an error when trying to generate docs (sbt doc). To fix, I have removed this flag from Compile / doc scope in build.sbt like so:

scalacOptions in(Compile, doc) := scalacOptions.value.filterNot(Seq("-P:silencer:checkUnused").contains)

Although perhaps the flag could also only be applied to the Compile / compile scope:

scalacOptions in(Compile, compile) ++= Seq("-P:silencer:checkUnused")

[seglo]

I ran into the same issue using another silencer parameter (pathFilter).

EDIT: my workaround

.settings(
  scalacOptions += "-P:silencer:pathFilters=src_managed",
  Compile / doc / scalacOptions := scalacOptions.value.filterNot(_.startsWith("-P:silencer"))
)

[ghik]

Seems like sbt does not enable compiler plugins when generating documentation.
It should be easy to do that manually but currently I don't know exactly how to do it. Here's a SO question about that: https://stackoverflow.com/questions/59625041/how-to-enable-compiler-plugin-in-scaladoc.

Currently the best solution is to manually filter out plugin related compiler options when running doc, just like @solarmosaic-kflorence did.

[eed3si9n]

@ghik

Seems like sbt does not enable compiler plugins when generating documentation.

Is this true? I just called show utilLogging/Compile/doc/scalacOptions on the project that uses silencer and it include -Xplugin.

sbt:sbtRoot> show utilLogging/Compile/scalacOptions
[info] * -encoding
[info] * utf8
[info] * -deprecation
[info] * -feature
[info] * -unchecked
[info] * -Xlint
[info] * -language:higherKinds
[info] * -language:implicitConversions
[info] * -Xfuture
[info] * -Xlint
[info] * -Xfatal-warnings
[info] * -Yno-adapted-args
[info] * -Ywarn-dead-code
[info] * -Ywarn-numeric-widen
[info] * -Ywarn-value-discard
[info] * -Ywarn-unused-import
[info] * -Xplugin:/Users/eed3si9n/.coursier/cache/v1/https/repo1.maven.org/maven2/com/github/ghik/silencer-plugin_2.12/1.4.2/silencer-plugin_2.12-1.4.2.jar
[info] * -Ywarn-unused:-locals,-explicits,-privates
[success] Total time: 0 s, completed Jan 8, 2020 1:35:30 PM
sbt:sbtRoot> show utilLogging/Compile/doc/scalacOptions
[info] * -encoding
[info] * utf8
[info] * -deprecation
[info] * -feature
[info] * -unchecked
[info] * -Xlint
[info] * -language:higherKinds
[info] * -language:implicitConversions
[info] * -Xfuture
[info] * -Xlint
[info] * -Xfatal-warnings
[info] * -Yno-adapted-args
[info] * -Ywarn-dead-code
[info] * -Ywarn-numeric-widen
[info] * -Ywarn-value-discard
[info] * -Ywarn-unused-import
[info] * -Xplugin:/Users/eed3si9n/.coursier/cache/v1/https/repo1.maven.org/maven2/com/github/ghik/silencer-plugin_2.12/1.4.2/silencer-plugin_2.12-1.4.2.jar
[info] * -Ywarn-unused:-locals,-explicits,-privates
[info] * -sourcepath
[info] * /Users/eed3si9n/work/sbt-modules/sbt
[info] * -doc-source-url
[info] * https://github.com/sbt/sbt/tree/b37bad6644da01937fac6eabc798bc670742da24€{FILE_PATH}.scala
[success] Total time: 0 s, completed Jan 8, 2020 1:35:36 PM

[eed3si9n]

And here's wtih Compile / scalacOptions ++= Seq("-P:silencer:checkUnused")

sbt:sbtRoot> show utilLogging/Compile/scalacOptions
[info] * -encoding
[info] * utf8
[info] * -deprecation
[info] * -feature
[info] * -unchecked
[info] * -Xlint
[info] * -language:higherKinds
[info] * -language:implicitConversions
[info] * -Xfuture
[info] * -Xlint
[info] * -Xfatal-warnings
[info] * -Yno-adapted-args
[info] * -Ywarn-dead-code
[info] * -Ywarn-numeric-widen
[info] * -Ywarn-value-discard
[info] * -Ywarn-unused-import
[info] * -Xplugin:/Users/eed3si9n/.coursier/cache/v1/https/repo1.maven.org/maven2/com/github/ghik/silencer-plugin_2.12/1.4.2/silencer-plugin_2.12-1.4.2.jar
[info] * -Ywarn-unused:-locals,-explicits,-privates
[info] * -P:silencer:checkUnused
[success] Total time: 0 s, completed Jan 8, 2020 1:57:48 PM
sbt:sbtRoot> show utilLogging/Compile/doc/scalacOptions
[info] * -encoding
[info] * utf8
[info] * -deprecation
[info] * -feature
[info] * -unchecked
[info] * -Xlint
[info] * -language:higherKinds
[info] * -language:implicitConversions
[info] * -Xfuture
[info] * -Xlint
[info] * -Xfatal-warnings
[info] * -Yno-adapted-args
[info] * -Ywarn-dead-code
[info] * -Ywarn-numeric-widen
[info] * -Ywarn-value-discard
[info] * -Ywarn-unused-import
[info] * -Xplugin:/Users/eed3si9n/.coursier/cache/v1/https/repo1.maven.org/maven2/com/github/ghik/silencer-plugin_2.12/1.4.2/silencer-plugin_2.12-1.4.2.jar
[info] * -Ywarn-unused:-locals,-explicits,-privates
[info] * -P:silencer:checkUnused
[info] * -sourcepath
[info] * /Users/eed3si9n/work/sbt-modules/sbt
[info] * -doc-source-url
[info] * https://github.com/sbt/sbt/tree/b37bad6644da01937fac6eabc798bc670742da24€{FILE_PATH}.scala
[success] Total time: 0 s, completed Jan 8, 2020 1:57:51 PM

[ghik]

Thanks @eed3si9n, that's interesting. Then it seems that silencer was somehow not properly enabled for doc in projects of @solarmosaic-kflorence and @seglo - can you please share your build.sbt or an example project?

[seglo]

@ghik The project I'm working with is https://github.com/akka/alpakka. The solution @eed3si9n proposed by omitting the intask component when defining the scope on scalacOptions seems to work, but I had already merged my workaround.

And here's wtih Compile / scalacOptions ++= Seq("-P:silencer:checkUnused")

Before the workaround (akka/alpakka#2077) the build would fail during our snapshot publishing step, on the doc task.

sbt ";++2.13.1;google-cloud-pub-sub-grpc / Compile / doc"

[solarmosaic-kflorence]

I believe my build.sbt conforms exactly to how the plugin is documented in the readme.md:

object Dependencies {
  val silencerLib = "com.github.ghik" % "silencer-lib" % Versions.Silencer % Provided
  val silencerPlugin = "com.github.ghik" % "silencer-plugin" % Versions.Silencer
}

object Versions {
  val Silencer = "1.4.4"
}

lazy val foo = (project in file("foo"))
  .settings(
    libraryDependencies ++= Seq(
        compilerPlugin(Dependencies.silencerPlugin).cross(CrossVersion.full),
        Dependencies.silencerLib.cross(CrossVersion.full)
    ),
    scalacOptions ++= Seq(
      "-P:silencer:checkUnused",
      ...
    )
  )

So is another fix to use Compile / scalacOptions += "-P:silencer:checkUnused" instead? If so perhaps it should also be documented that way.