From 6b82a8d07e3c46debdfb6a038b84bbc731276a2b Mon Sep 17 00:00:00 2001
From: Ethan Atkins <ethan.atkins@gmail.com>
Date: Sat, 23 Mar 2019 11:04:44 -0700
Subject: [PATCH] Don't use usingTerminal

The usingTerminal method synchronizes the JLine object which can lead to
deadlock if multiple threads call it. When we just to want to read the
attributes of the terminal, but not modify it, there doesn't seem to be
any reason to use a lock.
---
 .../src/main/scala/sbt/internal/util/LineReader.scala         | 2 +-
 main/src/main/scala/sbt/CommandLineUIService.scala            | 4 ++--
 main/src/main/scala/sbt/internal/SettingGraph.scala           | 2 +-
 main/src/main/scala/sbt/internal/TaskProgress.scala           | 2 +-
 4 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/internal/util-complete/src/main/scala/sbt/internal/util/LineReader.scala b/internal/util-complete/src/main/scala/sbt/internal/util/LineReader.scala
index 34153e45d..ddf48ad34 100644
--- a/internal/util-complete/src/main/scala/sbt/internal/util/LineReader.scala
+++ b/internal/util-complete/src/main/scala/sbt/internal/util/LineReader.scala
@@ -127,7 +127,7 @@ private[sbt] object JLine {
 
   // When calling this, ensure that enableEcho has been or will be called.
   // TerminalFactory.get will initialize the terminal to disable echo.
-  private def terminal = jline.TerminalFactory.get
+  private[sbt] def terminal = jline.TerminalFactory.get
 
   private def withTerminal[T](f: jline.Terminal => T): T =
     synchronized {
diff --git a/main/src/main/scala/sbt/CommandLineUIService.scala b/main/src/main/scala/sbt/CommandLineUIService.scala
index bf4da75da..e88521268 100644
--- a/main/src/main/scala/sbt/CommandLineUIService.scala
+++ b/main/src/main/scala/sbt/CommandLineUIService.scala
@@ -27,9 +27,9 @@ trait CommandLineUIService extends InteractionService {
     }
   }
 
-  override def terminalWidth: Int = JLine.usingTerminal(_.getWidth)
+  override def terminalWidth: Int = JLine.terminal.getWidth
 
-  override def terminalHeight: Int = JLine.usingTerminal(_.getHeight)
+  override def terminalHeight: Int = JLine.terminal.getHeight
 }
 
 object CommandLineUIService extends CommandLineUIService
diff --git a/main/src/main/scala/sbt/internal/SettingGraph.scala b/main/src/main/scala/sbt/internal/SettingGraph.scala
index 118c568cc..77e33c097 100644
--- a/main/src/main/scala/sbt/internal/SettingGraph.scala
+++ b/main/src/main/scala/sbt/internal/SettingGraph.scala
@@ -82,7 +82,7 @@ object Graph {
   // [info]   |
   // [info]   +-quux
   def toAscii[A](top: A, children: A => Seq[A], display: A => String, defaultWidth: Int): String = {
-    val maxColumn = math.max(JLine.usingTerminal(_.getWidth), defaultWidth) - 8
+    val maxColumn = math.max(JLine.terminal.getWidth, defaultWidth) - 8
     val twoSpaces = " " + " " // prevent accidentally being converted into a tab
     def limitLine(s: String): String =
       if (s.length > maxColumn) s.slice(0, maxColumn - 2) + ".."
diff --git a/main/src/main/scala/sbt/internal/TaskProgress.scala b/main/src/main/scala/sbt/internal/TaskProgress.scala
index d73452355..d3120e2dd 100644
--- a/main/src/main/scala/sbt/internal/TaskProgress.scala
+++ b/main/src/main/scala/sbt/internal/TaskProgress.scala
@@ -25,7 +25,7 @@ private[sbt] final class TaskProgress
   private[this] val isStopped = new AtomicBoolean(false)
 
   override def initial(): Unit = {
-    ConsoleAppender.setTerminalWidth(JLine.usingTerminal(_.getWidth))
+    ConsoleAppender.setTerminalWidth(JLine.terminal.getWidth)
   }
 
   override def afterReady(task: Task[_]): Unit = {