Merge pull request scala#2562 from som-snytt/issue/double-plugin

SI-7494 Each plugin must only be instantiated once.

Author: retronym

src/compiler/scala/tools/nsc/plugins/Plugin.scala

@@ -93,15 +93,13 @@ object Plugin {
   type AnyClass = Class[_]
 
   /** Use a class loader to load the plugin class.
-   *
-   *  @return `None` on failure
    */
-  def load(pd: PluginDescription, loader: ClassLoader): Try[AnyClass] = {
+  def load(classname: String, loader: ClassLoader): Try[AnyClass] = {
     Try[AnyClass] {
-      loader loadClass pd.classname
+      loader loadClass classname
     } recoverWith {
       case _: Exception =>
-        Failure(new RuntimeException(s"Warning: class not found: ${pd.classname}"))
+        Failure(new RuntimeException(s"Warning: class not found: ${classname}"))
     }
   }
 
@@ -137,9 +135,8 @@ object Plugin {
       case _                   => false
     }
     val (locs, pds) = ((explicit ::: exploded ::: included) filterNot ignored).unzip
-
     val loader = loaderFor(locs.distinct)
-    pds filter (_.isSuccess) map (_.get) map (Plugin load (_, loader))
+    (pds filter (_.isSuccess) map (_.get.classname)).distinct map (Plugin load (_, loader))
   }
 
   /** Instantiate a plugin class, given the class and

src/partest/scala/tools/partest/nest/Runner.scala

@@ -13,6 +13,7 @@ import java.util.concurrent.TimeUnit.NANOSECONDS
 import scala.collection.mutable.ListBuffer
 import scala.concurrent.duration.Duration
 import scala.io.Codec
+import scala.reflect.internal.FatalError
 import scala.sys.process.Process
 import scala.tools.nsc.Properties.{ envOrElse, isWin, jdkHome, javaHome, propOrElse, propOrEmpty, setProp }
 import scala.tools.nsc.{ Settings, CompilerCommand, Global }
@@ -451,9 +452,10 @@ class Runner(val testFile: File, fileManager: FileManager, val testRunParams: Te
     val failing = rounds find (x => nextTestActionExpectTrue("compilation failed", x.isOk) == false)
 
     // which means passing if it checks and didn't crash the compiler
+    // or, OK, we'll let you crash the compiler with a FatalError if you supply a check file
     def checked(r: CompileRound) = r.result match {
-      case f: Crash => false
-      case f        => normalizeLog(); diffIsOk
+      case Crash(_, t, _) if !checkFile.canRead || !t.isInstanceOf[FatalError] => false
+      case _ => normalizeLog(); diffIsOk
     }
 
     failing map (checked) getOrElse nextTestActionFailing("expected compilation failure")

test/pending/neg/plugin-after-terminal.check renamed to test/files/neg/t7494-after-terminal.check

@@ -0,0 +1 @@
+-Xplugin:. -Xplugin-require:afterterminal

test/pending/neg/plugin-after-terminal/src/ThePlugin.scala renamed to test/files/neg/t7494-after-terminal/ThePlugin.scala

@@ -0,0 +1,6 @@
+
+package sample
+
+// just a sample that is compiled with the sample plugin enabled
+object Sample extends App {
+}

test/files/neg/t7494-after-terminal/sample_2.flags

@@ -1,5 +1,5 @@
 <plugin>
-  <name>beforeparser</name>
+  <name>ignored</name>
   <classname>scala.test.plugins.ThePlugin</classname>
 </plugin>
 

test/files/neg/t7494-after-terminal/sample_2.scala

@@ -0,0 +1 @@
+-Xplugin:. -Xplugin-require:beforeparser