Added a MissingRequirementError variant of Fata...

Added a MissingRequirementError variant of FatalError so as to
improve the amazingly confusing "class file is broken" message which
people get whenever they are missing a dependency. Before: class file
'jdo2-api-2.3-SNAPSHOT.jar(javax/jdo/Transaction.class)' is broken
After: Missing dependency 'class javax.transaction.Synchronization',
required by jdo2-api-2.3-SNAPSHOT.jar(javax/jdo/Transaction.class)

3 files changed, 13 insertions, 3 deletions

diff --git a/src/compiler/scala/tools/nsc/FatalError.scala b/src/compiler/scala/tools/nsc/FatalError.scala
index 9d219410e2..836bd79175 100644
--- a/src/compiler/scala/tools/nsc/FatalError.scala
+++ b/src/compiler/scala/tools/nsc/FatalError.scala
@@ -7,3 +7,10 @@
 package scala.tools.nsc
 
 case class FatalError(msg: String) extends Exception(msg)
+class MissingRequirementError(val req: String) extends FatalError(req + " not found.")
+object MissingRequirementError {
+  def unapply(x: Throwable) = x match {
+    case x: MissingRequirementError => Some(x.req)
+    case _                          => None
+  }
+}
diff --git a/src/compiler/scala/tools/nsc/symtab/Definitions.scala b/src/compiler/scala/tools/nsc/symtab/Definitions.scala
index f16a7d2716..559f3f5890 100644
--- a/src/compiler/scala/tools/nsc/symtab/Definitions.scala
+++ b/src/compiler/scala/tools/nsc/symtab/Definitions.scala
@@ -399,7 +399,7 @@ trait Definitions {
       if (result == NoSymbol) {
         if (settings.debug.value)
           { Console.println(sym.info); Console.println(sym.info.members) }//debug
-        throw new FatalError((if (module) "object " else "class ") + fullname + " not found.")
+        throw new MissingRequirementError((if (module) "object " else "class ") + fullname)
       }
       result
     }
diff --git a/src/compiler/scala/tools/nsc/symtab/classfile/ClassfileParser.scala b/src/compiler/scala/tools/nsc/symtab/classfile/ClassfileParser.scala
index 426a9d4a52..a4dcdc8fee 100644
--- a/src/compiler/scala/tools/nsc/symtab/classfile/ClassfileParser.scala
+++ b/src/compiler/scala/tools/nsc/symtab/classfile/ClassfileParser.scala
@@ -51,6 +51,9 @@ abstract class ClassfileParser {
   }
 
   def parse(file: AbstractFile, root: Symbol) = try {
+    def handleMissing(e: MissingRequirementError) =
+      throw new IOException("Missing dependency '" + e.req + "', required by " + in.file)
+
     def handleError(e: Exception) = {
       if (settings.debug.value) e.printStackTrace()
       throw new IOException("class file '" + in.file + "' is broken\n(" + {
@@ -84,8 +87,8 @@ abstract class ClassfileParser {
       this.pool = new ConstantPool
       parseClass()
     } catch {
-      case e: FatalError => handleError(e)
-      case e: RuntimeException => handleError(e)
+      case e: MissingRequirementError => handleMissing(e)
+      case e: RuntimeException        => handleError(e)
     }
   } finally {
     busy = false