SI-4563 friendlier behavior for Ctrl+D in the REPL

Closing the REPL with Ctrl+D does not issue a newline, so the user's
prompt displays on the same line as the `scala>` prompt. This is bad.
We now force a newline before closing the interpreter, and display
`:quit` while we're at it so that people know how to exit the REPL
(since `exit` doesn't exist anymore).

The tricky part was to only add a newline when the console is
interrupted, and *not* when it is closed by a command (like `:quit`),
since commands are processed after their text (including newline) has
been sent to the console.

1 files changed, 8 insertions, 1 deletions

diff --git a/src/repl/scala/tools/nsc/interpreter/ILoop.scala b/src/repl/scala/tools/nsc/interpreter/ILoop.scala
index ce0eadc04f..50c89f7442 100644
--- a/src/repl/scala/tools/nsc/interpreter/ILoop.scala
+++ b/src/repl/scala/tools/nsc/interpreter/ILoop.scala
@@ -430,7 +430,14 @@ class ILoop(in0: Option[BufferedReader], protected val out: JPrintWriter)
     import scala.concurrent.duration._
     Await.ready(globalFuture, 60.seconds)
 
-    (line ne null) && (command(line) match {
+    if (line eq null) {
+      // SI-4563: this means the console was properly interrupted (Ctrl+D usually)
+      // so we display the output message (which by default ends with
+      // a newline so as not to break the user's terminal)
+      if (in.interactive) out.print(Properties.shellInterruptedString)
+
+      false
+    } else (command(line) match {
       case Result(false, _)      => false
       case Result(_, Some(line)) => addReplay(line) ; true
       case _                     => true