SD-256 enable colored output by default on unix

`scala.color` now has 3 states: `true`, `false` and `auto`
(the default). `auto` allows colors if not on windows and if the shell
is interactive (as in, both stdin and stdout are a tty).

The autodetect works as expected when run via SBT too, and it can always
be overriden on the CLI or via JAVA_OPTS.

1 files changed, 6 insertions, 0 deletions

diff --git a/src/library/scala/util/Properties.scala b/src/library/scala/util/Properties.scala
index 7b21351cf6..29a635fcbe 100644
--- a/src/library/scala/util/Properties.scala
+++ b/src/library/scala/util/Properties.scala
@@ -154,6 +154,12 @@ private[scala] trait PropertiesTrait {
   /* Some runtime values. */
   private[scala] def isAvian = javaVmName contains "Avian"
 
+  private[scala] def coloredOutputEnabled: Boolean = propOrElse("scala.color", "auto") match {
+    case "auto" => System.console() != null && !isWin
+    case a if a.toLowerCase() == "true" => true
+    case _ => false
+  }
+
   // This is looking for javac, tools.jar, etc.
   // Tries JDK_HOME first, then the more common but likely jre JAVA_HOME,
   // and finally the system property based javaHome.