From b90fc130ffc6bae78d55213879f855d7d5396624 Mon Sep 17 00:00:00 2001
From: Marek Safar <marek.safar@gmail.com>
Date: Mon, 3 Feb 2014 20:27:58 +0100
Subject: [PATCH] [corlib] Allow to use custom comparer when sorting null
 values.

---
 mcs/class/corlib/System/Array.cs          |  6 +-----
 mcs/class/corlib/Test/System/ArrayTest.cs | 21 +++++++++++++++++++++
 2 files changed, 22 insertions(+), 5 deletions(-)

diff --git a/mcs/class/corlib/System/Array.cs b/mcs/class/corlib/System/Array.cs
index e1fc50b210b..bc22c019faa 100644
--- a/mcs/class/corlib/System/Array.cs
+++ b/mcs/class/corlib/System/Array.cs
@@ -2557,11 +2557,7 @@ namespace System
 					// switch to insertion sort
 					for (i = low + 1; i <= high; i++) {
 						for (k = i; k > low; k--) {
-							// if keys[k] >= keys[k-1], break
-							if (array[k-1] == null)
-								break;
-							
-							if (array[k] != null && compare (array[k], array[k-1]) >= 0)
+							if (compare (array[k], array[k-1]) >= 0)
 								break;
 							
 							swap<T> (array, k - 1, k);
diff --git a/mcs/class/corlib/Test/System/ArrayTest.cs b/mcs/class/corlib/Test/System/ArrayTest.cs
index 71a21049911..eab4c40e143 100644
--- a/mcs/class/corlib/Test/System/ArrayTest.cs
+++ b/mcs/class/corlib/Test/System/ArrayTest.cs
@@ -2510,6 +2510,27 @@ public class ArrayTest
 		}
 	}
 
+	[Test]
+	public void Sort_NullValues ()
+	{
+		var s = new [] { "a", null, "b", null };
+		Array.Sort (s, (a, b) => {
+			if (a == null) {
+				return b == null ? 0 : 1;
+			}
+
+			if (b == null)
+				return -1;
+
+			return a.CompareTo (b);
+		});
+
+		Assert.AreEqual ("a", s [0], "#1");
+		Assert.AreEqual ("b", s [1], "#2");
+		Assert.IsNull (s [2], "#3");
+		Assert.IsNull (s [3], "#4");
+	}
+
 	[Test] // #616416
 	public void SortNonGenericDoubleItems () {
             double[] doubleValues = new double[11];
-- 
2.25.1