title: Why is there no Main-Class attribute in generated manifest?
body: <p>I have a build.sbt file that includes the assembly plugin.  Up until the most recent build, the Main-Class attribute was being included in the assembled far jar, but all of a sudden, this is no longer the case.</p>
  
  <p>When I attempt to run the jar, I get the inimitable:</p>
  
  <pre><code>no main manifest attribute, in ./target/scala-2.10/foo-0.3.0-SNAPSHOT.jar
  </code></pre>
  
  <p>but using run from the sbt console, works fine.</p>
  
  <p>My build.sbt currently looks like this (the mainClass in assembly added in an attempt to force indicate to the assembly plugin that it really should include, though I noticed in the plugin source code, it looks like it's checking the one specified for run anyway).</p>
  
  <pre><code>import AssemblyKeys._
  
  name := "foo"
  
  version := "0.3.0-SNAPSHOT"
  
  organization := "com.mycompany.myproduct"
  
  scalaVersion := "2.10.4"
  
  mainClass in (Compile, run) := Some("ProcessRelogger")
  
  mainClass in assembly := Some("ProcessRelogger")
  
  assemblySettings
  
  libraryDependencies ++= Seq(
    "org.scalatest" % "scalatest_2.10" % "1.9.2" % "test",
    "ch.qos.logback" % "logback-classic" % "1.0.9",
    "com.typesafe.akka" %% "akka-actor" % "2.2.4",
    "joda-time" % "joda-time" % "2.3",
    "com.rabbitmq" % "amqp-client" % "3.3.4",
    "org.scalaz" % "scalaz-core_2.10" % "7.0.6",
    "com.typesafe.slick" %% "slick" % "2.0.2",
    "postgresql" % "postgresql" % "9.1-901.jdbc4",
    "com.escalatesoft.subcut" %% "subcut" % "2.0"
  )
  </code></pre>
  
  <p>and when I unzip the jar file, and check META-INF/MANIFEST.MF, there's no Main-Class: attribute included.</p>