[xlinq] fix bug #23318 - XComment.ToString() accepts "invalid" values.

Before it passes the value to XmlWriter.WriteComment(), it replaces
invalid values to valid form.

3 files changed, 71 insertions, 1 deletions

diff --git a/mcs/class/System.Xml.Linq/System.Xml.Linq/XComment.cs b/mcs/class/System.Xml.Linq/System.Xml.Linq/XComment.cs
index edab3fb4775..f7b5e7b6c66 100644
--- a/mcs/class/System.Xml.Linq/System.Xml.Linq/XComment.cs
+++ b/mcs/class/System.Xml.Linq/System.Xml.Linq/XComment.cs
@@ -25,6 +25,7 @@
 //
 
 using System;
+using System.Linq;
 using System.Xml;
 
 namespace System.Xml.Linq
@@ -54,7 +55,9 @@ namespace System.Xml.Linq
 
 		public override void WriteTo (XmlWriter writer)
 		{
-			writer.WriteComment (value);
+			var v = value.Replace ("--", "- -");
+			v = v.LastOrDefault () == '-' ? v.Substring (0, v.Length - 1) +"&#2D;" : v;
+			writer.WriteComment (v);
 		}
 	}
 }
diff --git a/mcs/class/System.Xml.Linq/System.Xml.Linq_test.dll.sources b/mcs/class/System.Xml.Linq/System.Xml.Linq_test.dll.sources
index 77007ae238d..693d4a2e296 100644
--- a/mcs/class/System.Xml.Linq/System.Xml.Linq_test.dll.sources
+++ b/mcs/class/System.Xml.Linq/System.Xml.Linq_test.dll.sources
@@ -1,5 +1,6 @@
 System.Xml.Linq/ExtensionsTest.cs
 System.Xml.Linq/XAttributeTest.cs
+System.Xml.Linq/XCommentTest.cs
 System.Xml.Linq/XDocumentTest.cs
 System.Xml.Linq/XElementTest.cs
 System.Xml.Linq/XNameTest.cs
diff --git a/mcs/class/System.Xml.Linq/Test/System.Xml.Linq/XCommentTest.cs b/mcs/class/System.Xml.Linq/Test/System.Xml.Linq/XCommentTest.cs
new file mode 100644
index 00000000000..b324bb68fcc
--- /dev/null
+++ b/mcs/class/System.Xml.Linq/Test/System.Xml.Linq/XCommentTest.cs
@@ -0,0 +1,66 @@
+//
+// Authors:
+//   Atsushi Enomoto
+//
+// Copyright 2014 Xamarin Inc. (http://www.xamarin.com)
+//
+// Permission is hereby granted, free of charge, to any person obtaining
+// a copy of this software and associated documentation files (the
+// "Software"), to deal in the Software without restriction, including
+// without limitation the rights to use, copy, modify, merge, publish,
+// distribute, sublicense, and/or sell copies of the Software, and to
+// permit persons to whom the Software is furnished to do so, subject to
+// the following conditions:
+// 
+// The above copyright notice and this permission notice shall be
+// included in all copies or substantial portions of the Software.
+// 
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+//
+
+using System;
+using System.IO;
+using System.Xml;
+using System.Xml.Linq;
+using System.Linq;
+
+using NUnit.Framework;
+
+namespace MonoTests.System.Xml.Linq
+{
+	[TestFixture]
+	public class XCommentTest
+	{
+		[Test]
+		public void EscapeSequentialDashes ()
+		{
+			XComment c;
+
+			c = new XComment ("<--foo-->");
+			Assert.AreEqual ("<--foo-->", c.Value, "#1");
+			// bug #23318
+			// Unlike XmlWriter.WriteComment(), XComment.ToString() seems to accept "--" in the value.
+			Assert.AreEqual ("<!--<- -foo- ->-->", c.ToString (), "#2");
+			// make sure if it can be read...
+			XmlReader.Create (new StringReader (c.ToString ())).Read ();
+
+			// The last '-' causes some glitch...
+			c = new XComment ("--foo--");
+			Assert.AreEqual ("--foo--", c.Value, "#3");
+			Assert.AreEqual ("<!--- -foo- &#2D;-->", c.ToString (), "#4");
+			XmlReader.Create (new StringReader (c.ToString ())).Read ();
+
+			// What if <!-- appears in the value?
+			c = new XComment ("<!--foo-->");
+			Assert.AreEqual ("<!--foo-->", c.Value, "#5");
+			Assert.AreEqual ("<!--<!- -foo- ->-->", c.ToString (), "#6");
+			XmlReader.Create (new StringReader (c.ToString ())).Read ();
+		}
+	}
+}