Play’s Build.scala File- a Very Subtle Gotcha

Work on the new module repository for Play is progressing nicely, but a very subtle bug was introduced into the Build.scala file. As a result, artifacts from the first repository were not being found. Can you spot the difference here? The first code snippet is correct, and the second is faulty.

val main = PlayProject(appName, appVersion, appDependencies, mainLang = JAVA).settings (
    resolvers += Resolver.url("Objectify Play Repository", url("http://schaloner.github.com/releases/"))(Resolver.ivyStylePatterns),
    resolvers += Resolver.url("Scala Tools", url("http://scala-tools.org/repo-releases/"))(Resolver.ivyStylePatterns)
  )

val main = PlayProject(appName, appVersion, appDependencies, mainLang = JAVA).settings {
    resolvers += Resolver.url("Objectify Play Repository", url("http://schaloner.github.com/releases/"))(Resolver.ivyStylePatterns)
    resolvers += Resolver.url("Scala Tools", url("http://scala-tools.org/repo-releases/"))(Resolver.ivyStylePatterns)
  }

The problem was caused by using curly brackets instead of parentheses. Note also that when using curly brackets, you can’t put a comma after the first resolver. However, the file still compiles without a problem. Very subtle, very annoying!

So, the correct form is the first snippet above – here with bold to emphasise the key points.

val main = PlayProject(appName, appVersion, appDependencies, mainLang = JAVA).settings (
    resolvers += Resolver.url("Objectify Play Repository", url("http://schaloner.github.com/releases/"))(Resolver.ivyStylePatterns),
    resolvers += Resolver.url("Scala Tools", url("http://scala-tools.org/repo-releases/"))(Resolver.ivyStylePatterns)
  )