From d7ca9c5637f488ced21788bde9df15fcf0c6644a Mon Sep 17 00:00:00 2001
From: Havoc Pennington <hp@pobox.com>
Date: Fri, 15 Aug 2014 15:24:21 -0400
Subject: [PATCH] Server launcher: Print errors running java -version to stderr

We forward errors from the spawned server to stderr, so we are
already using stderr and this should save someone some pain
vs. just swallowing the fail.
---
 launch/src/main/scala/xsbt/boot/ServerApplication.scala | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/launch/src/main/scala/xsbt/boot/ServerApplication.scala b/launch/src/main/scala/xsbt/boot/ServerApplication.scala
index c8123bcb9..9194e1ff1 100644
--- a/launch/src/main/scala/xsbt/boot/ServerApplication.scala
+++ b/launch/src/main/scala/xsbt/boot/ServerApplication.scala
@@ -225,7 +225,9 @@ object ServerLauncher {
       val re = """java version "[0-9]+\.([0-9]+)\..*".*""".r
       lineOption flatMap {
         case re(v) => try Some(Integer.parseInt(v) > version) catch { case NonFatal(_) => None }
-        case other => None
+        case other =>
+          System.err.println(s"Failed to parse version from 'java -version' output '$other'")
+          None
       }
     } finally {
       process.destroy()
@@ -235,6 +237,7 @@ object ServerLauncher {
     case e: IOException =>
       // both process.start and reading the output streams can throw IOException.
       // all OS exceptions from process.start are supposed to be IOException.
+      System.err.println(s"Failed to run 'java -version': ${e.getClass.getName}: ${e.getMessage}")
       None
   }