Backport of r25661 and r25664.

Author: Antonio Cunei

src/compiler/scala/tools/nsc/interactive/CompilerControl.scala

@@ -167,7 +167,9 @@ trait CompilerControl { self: Global =>
   def askScopeCompletion(pos: Position, response: Response[List[Member]]) =
     postWorkItem(new AskScopeCompletionItem(pos, response))
 
-  /** Asks to do unit corresponding to given source file on present and subsequent type checking passes */
+  /** Asks to do unit corresponding to given source file on present and subsequent type checking passes.
+   *  If the file is in the 'crashedFiles' ignore list it is removed and typechecked normally.
+   */
   def askToDoFirst(source: SourceFile) =
     postWorkItem(new AskToDoFirstItem(source))
 
@@ -315,7 +317,10 @@ trait CompilerControl { self: Global =>
   }
 
   class AskToDoFirstItem(val source: SourceFile) extends WorkItem {
-    def apply() = moveToFront(List(source))
+    def apply() = {
+      moveToFront(List(source))
+      enableIgnoredFile(source.file)
+    }
     override def toString = "dofirst "+source
 
     def raiseMissing() = ()

src/compiler/scala/tools/nsc/interactive/Global.scala

@@ -48,7 +48,6 @@ class Global(settings: Settings, reporter: Reporter, projectName: String = "")
     else NullLogger
 
   import log.logreplay
-  debugLog("interactive compiler from 20 Feb")
   debugLog("logger: " + log.getClass + " writing to " + (new java.io.File(logName)).getAbsolutePath)
   debugLog("classpath: "+classPath)
 
@@ -161,6 +160,25 @@ class Global(settings: Settings, reporter: Reporter, projectName: String = "")
    */
   protected var allSources: List[SourceFile] = List()
 
+  private var lastException: Option[Throwable] = None
+
+  /** A list of files that crashed the compiler. They will be ignored during background
+   *  compilation until they are removed from this list.
+   */
+  private var ignoredFiles: Set[AbstractFile] = Set()
+
+  /** Flush the buffer of sources that are ignored during background compilation. */
+  def clearIgnoredFiles() {
+    ignoredFiles = Set()
+  }
+
+  /** Remove a crashed file from the ignore buffer. Background compilation will take it into account
+   *  and errors will be reported against it. */
+  def enableIgnoredFile(file: AbstractFile) {
+    ignoredFiles -= file
+    debugLog("Removed crashed file %s. Still in the ignored buffer: %s".format(file, ignoredFiles))
+  }
+
   /** The currently active typer run */
   private var currentTyperRun: TyperRun = _
   newTyperRun()
@@ -440,12 +458,33 @@ class Global(settings: Settings, reporter: Reporter, projectName: String = "")
     }
 
     // ensure all loaded units are typechecked
-    for (s <- allSources; unit <- getUnit(s)) {
-      if (!unit.isUpToDate) typeCheck(unit)
-      else debugLog("already up to date: "+unit)
-      for (r <- waitLoadedTypeResponses(unit.source))
-        r set unit.body
-      serviceParsedEntered()
+    for (s <- allSources; if !ignoredFiles(s.file); unit <- getUnit(s)) {
+      try {
+        if (!unit.isUpToDate)
+          if (unit.problems.isEmpty || !settings.YpresentationStrict.value)
+            typeCheck(unit)
+          else debugLog("%s has syntax errors. Skipped typechecking".format(unit))
+        else debugLog("already up to date: "+unit)
+        for (r <- waitLoadedTypeResponses(unit.source))
+          r set unit.body
+        serviceParsedEntered()
+      } catch {
+        case ex: FreshRunReq => throw ex // propagate a new run request
+
+        case ex =>
+          println("[%s]: exception during background compile: ".format(unit.source) + ex)
+          ex.printStackTrace()
+          for (r <- waitLoadedTypeResponses(unit.source)) {
+            r.raise(ex)
+          }
+          serviceParsedEntered()
+
+          lastException = Some(ex)
+          ignoredFiles += unit.source.file
+          println("[%s] marking unit as crashed (crashedFiles: %s)".format(unit, ignoredFiles))
+
+          reporter.error(unit.body.pos, "Presentation compiler crashed while type checking this file: %s".format(ex.toString()))
+      }
     }
 
     // clean out stale waiting responses
@@ -888,6 +927,8 @@ class Global(settings: Settings, reporter: Reporter, projectName: String = "")
         if (unit.isUpToDate) {
           debugLog("already typed");
           response set unit.body
+        } else if (ignoredFiles(source.file)) {
+          response.raise(lastException.getOrElse(CancelException))
         } else if (onSameThread) {
           getTypedTree(source, forceReload = false, response)
         } else {

src/compiler/scala/tools/nsc/settings/ScalaSettings.scala

@@ -155,6 +155,7 @@ trait ScalaSettings extends AbsScalaSettings with StandardScalaSettings {
    */
   val YpresentationVerbose = BooleanSetting("-Ypresentation-verbose", "Print information about presentation compiler tasks.")
   val YpresentationDebug   = BooleanSetting("-Ypresentation-debug",  "Enable debugging output for the presentation compiler.")
+  val YpresentationStrict  = BooleanSetting("-Ypresentation-strict", "Do not report type errors in sources with syntax errors.")
 
   val YpresentationLog     = StringSetting("-Ypresentation-log", "file", "Log presentation compiler events into file", "")
   val YpresentationReplay  = StringSetting("-Ypresentation-replay", "file", "Replay presentation compiler events from file", "")