value unsafePerformSync is not a member of scalaz.concurrent.Task[String]

Question

value unsafePerformSync is not a member of scalaz.concurrent.Task[String]
[error]     val x = task.unsafePerformSync
[error]                  ^
[error] one error found

How to resolve the above (2.11.8) scalac error? Thanks.

From the following code snippet:

import org.http4s._, org.http4s.dsl._                                  
import org.http4s.client.blaze._
import scalaz._, Scalaz._
import scalaz.concurrent.Task

object Client extends App {
  val client = PooledHttp1Client()
  val httpize = Uri.uri("http://httpize.herokuapp.com")

  def post() = {
    val req = Request(method = Method.POST, uri = httpize / "post").withBody("hello")
    val task = client.expect[String](req)
    val x = task.unsafePerformSync
    println(x)
}

Answer 1

Since the first 0.13 release http4s has been cross-published for Scalaz 7.1.x and 7.2.x. In Scalaz 7.1.x, the unsafePerformSync was simply run (which as a name is way too inviting for something that ideally you should never call directly, or at the very most once in your program).

So you have two choices. If you want to use Scalaz 7.2 (which you should unless you have other constraints), find a line like this in your build config:

libraryDependencies += "org.http4s" %% "http4s-core" % "0.15.0"

And change it to this:

libraryDependencies += "org.http4s" %% "http4s-core" % "0.15.0a"

Alternatively you could stick with Scalaz 7.1 and just change your code to use run.