Use unmanagedClasspath and allDependencies to determine firrtl dependency.

1 files changed, 13 insertions, 9 deletions

diff --git a/build.sbt b/build.sbt
index 4fd60fef..4ad1cf77 100644
--- a/build.sbt
+++ b/build.sbt
@@ -64,21 +64,25 @@ lazy val chiselSettings = Seq (
     Resolver.sonatypeRepo("releases")
   ),
 
-  libraryDependencies ++= Seq("firrtl").collect {
-    // If we have an unmanaged jar file in the lib directory, assume we're to use that,
-    case dep: String if (java.nio.file.Files.notExists(java.nio.file.Paths.get(s"${unmanagedBase.value}/$dep.jar"))) =>
-      //  otherwise let sbt fetch the appropriate version.
-      "edu.berkeley.cs" %% dep % sys.props.getOrElse(dep + "Version", defaultVersions(dep))
-      // This should really be something like:
-      //   case dep: String if !unmanagedClasspath.value.contains(s"$dep.jar") => "edu.berkeley.cs" %% dep % sys.props.getOrElse(dep + "Version", defaultVersions(dep))
-      //  but this generates - error: A setting cannot depend on a task
-  } ++ Seq(
+  libraryDependencies ++= Seq(
     "org.scalatest" %% "scalatest" % "2.2.5" % "test",
     "org.scala-lang" % "scala-reflect" % scalaVersion.value,
     "org.scalacheck" %% "scalacheck" % "1.12.4" % "test",
     "com.github.scopt" %% "scopt" % "3.4.0"
   ),
 
+  // Since we want to examine the classpath to determine if a dependency on firrtl is required,
+  //  this has to be a Task setting.
+  //  Fortunately, allDependencies is a Task Setting, so we can modify that.
+  allDependencies := {
+    allDependencies.value ++ Seq("firrtl").collect {
+      // If we have an unmanaged jar file on the classpath, assume we're to use that,
+      case dep: String if !(unmanagedClasspath in Compile).value.toString.contains(s"$dep.jar") =>
+        //  otherwise let sbt fetch the appropriate version.
+        "edu.berkeley.cs" %% dep % sys.props.getOrElse(dep + "Version", defaultVersions(dep))
+    }
+  },
+  
   // Tests from other projects may still run concurrently.
   parallelExecution in Test := true,