From c5df728176f05cd906535791a61aeea5b1b2f209 Mon Sep 17 00:00:00 2001
From: Andrew Schwartzmeyer <andrew@schwartzmeyer.com>
Date: Fri, 1 Jul 2016 11:51:12 -0700
Subject: [PATCH] Import PSReadLine change to throw when redirected

A similar change was made to the Source Depot fork of PSReadLine, and
the behavior is depended on in the ConsoleHost. The host always attempts
to load PSReadLine, because a future version of PSReadLine will support
redirected input/output, and until then, PSReadLine must throw so that
the host correctly falls back to Console.ReadLine().
---
 src/Microsoft.PowerShell.PSReadLine/ReadLine.cs | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/src/Microsoft.PowerShell.PSReadLine/ReadLine.cs b/src/Microsoft.PowerShell.PSReadLine/ReadLine.cs
index 58a9591dbe..aabf5a46a6 100644
--- a/src/Microsoft.PowerShell.PSReadLine/ReadLine.cs
+++ b/src/Microsoft.PowerShell.PSReadLine/ReadLine.cs
@@ -258,6 +258,14 @@ namespace Microsoft.PowerShell
         public static string ReadLine(Runspace runspace, EngineIntrinsics engineIntrinsics)
         {
             var console = _singleton._console;
+
+            // If either stdin or stdout is redirected, PSReadline doesn't really work, so throw
+            // and let PowerShell call Console.ReadLine or do whatever else it decides to do.
+            if (Console.IsInputRedirected || Console.IsOutputRedirected)
+            {
+                throw new NotSupportedException();
+            }
+
 #if CORECLR
             _singleton._prePSReadlineControlCMode = Console.TreatControlCAsInput;
 #else