how can I get around Target#apply() call cannot use....

[axaluss]

"Target#apply() call cannot use " + banned0.symbol + " defined within the T{...} block"

How am i supposed to work around this?
I want to compose several command calls into one command.

Some wiki entry describing this or a better error message would really help.

[lefou]

Can you show a snippet of your target and the full error message.

[axaluss]

Weird that m.publish works but _.scalaVersionShort() does not...

def publishAll(
      scalaVersion: String,
      sonatypeCreds: String,
      release: Boolean
    ): Command[Unit] =
    T.command {
      mainModule
        .millInternal
        .modules
        .collect {
          case m: PublishModule with Base =>
            m
        }
        .filter(_.scalaVersionShort() == scalaVersion)
        .foreach { m =>
          m.publish(sonatypeCreds, release = release, stagingRelease = false)
        }
    }
class Base  extends extends ScalaModule with PublishModule {
//.....
  override def scalaVersion: T[String] = T { scalaVersionLong }
}

build.sc:109: Target#apply() call cannot use `value x$12` defined within the T{...} block
        .filter(_.scalaVersion() == scalaVersion)
                ^
Compilation Failed

[lefou]

Sorry, I still don't understand. I can't see the definition of scalaVersionShort(). Also your snippet seems unrelated to the shown error message. I can't find the code from the error message anywhere.

[lefou]

Maybe your are looking for one of the combinators T.zip, T.traverse or T.sequence?

[axaluss]

def publishAll(
      scalaVersion: String,
      sonatypeCreds: String,
      release: Boolean
    ): Command[Unit] =
    T.command {
      mainModule
        .millInternal
        .modules
        .collect {
          case m: PublishModule with Base =>
            m
        }
        .filter(_.scalaVersion() == scalaVersion)
        .foreach { m =>
          m.publish(sonatypeCreds, release = release, stagingRelease = false)
        }
    }
class Base(_scalaVersionShort: String) extends ScalaModule with PublishModule {
//  val _scalaVersionShort: String         = ???
  override def scalaVersion: T[String] = T { _scalaVersionShort }
}

result:

build.sc:109: Target#apply() call cannot use `value x$12` defined within the T{...} block
        .filter(_.scalaVersion() == scalaVersion)
                ^
Compilation Failed

I then created a different version with a non T signature def scalaVersion: String= _scalaVersionShort
and changed the filter to .filter(_.scalaVersion == scalaVersion)
in which the call to m.publish(... works....

Why is the call to _.scalaVersion() a problem, but m.publish(... is not?

[lefou]

In your example you are collecting all PublishMoudles. After that you want to evaluate a target (scalaVersion) in these modules. And with the result, you want to evaluate another target (publish) for some modules. This kind of imperative evaluations isn't supported in a single run. But it is possible to realize this with a Evaluator Commands. With the evaluator at hand (injected as the first parameter), you can start multiple evaluations. Have have look at some other places where evaluator commands are used, e.g. GenIdea/idea.

[lefou]

It's probably because you are never executing the resulting publish target. I think you are just constructing a publish command in the foreach and then drop it. But you never call .apply() on in.

[axaluss]

Ah ok so both tasks scalaVersion and publish would be failing to compile if i would try to compose them.

Some chapter about working around call cannot use might be helpful for newcomers.

And I have to use a combination of T.zip, T.traverse or T.sequence instead to ship around the macro limitations?

[axaluss]

How could I compose existing commands and tasks etc into a new command In this example?

[lefou]

Se my other comment