[Mono-bugs] [Bug 81834][Nor] New - System.String.Format should make null object ""

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Changed by vgiszpenc at dsci.com.

http://bugzilla.ximian.com/show_bug.cgi?id=81834

--- shadow/81834	2007-06-08 14:46:41.000000000 -0400
+++ shadow/81834.tmp.7180	2007-06-08 14:46:41.000000000 -0400
@@ -0,0 +1,96 @@
+Bug#: 81834
+Product: Mono: Class Libraries
+Version: 1.2
+OS: All
+OS Details: 
+Status: NEW   
+Resolution: 
+Severity: 
+Priority: Normal
+Component: System
+AssignedTo: mono-bugs at ximian.com                            
+ReportedBy: vgiszpenc at dsci.com               
+QAContact: mono-bugs at ximian.com
+TargetMilestone: ---
+URL: 
+Cc: 
+Summary: System.String.Format should make null object ""
+
+Description of Problem:
+If you call System.String.Format and pass a valid format string and a null
+object, you should NOT get an exception according to Microsoft
+
+Copied from MSDN
+
+     index
+
+    A zero-based integer that indicates which element in a list of objects
+to format. If the object specified by index is a null reference (Nothing in
+Visual Basic), then the format item is replaced by the empty string ("").
+
+I noticed that StringBuilder has the same issue but uses different code to
+do similar stuff.
+
+
+Steps to reproduce the problem:
+class Test
+{
+	static void Main()
+	{
+		System.Console.WriteLine("Null object {0}", null);
+	}
+}
+
+class Test2
+{
+	static void Main()
+	{
+		System.Text.StringBuilder sb = new System.Text.StringBuilder();
+		sb.AppendFormat("Null test2 {0}", null);
+		System.Console.WriteLine(sb.ToString());
+	}
+}
+Actual Results:
+
+Unhandled Exception: System.ArgumentNullException: Argument cannot be null.
+  at System.String.FormatHelper (System.Text.StringBuilder result,
+IFormatProvider provider, System.String format, System.Object[] args) [0x00000]
+  at System.String.Format (IFormatProvider provider, System.String format,
+System.Object[] args) [0x00000]
+  at System.String.Format (System.String format, System.Object[] args)
+[0x00000]
+  at System.IO.TextWriter.Write (System.String format, System.Object[] arg)
+[0x00000]
+  at System.IO.TextWriter.WriteLine (System.String format, System.Object[]
+arg) [0x00000]
+  at System.Console.WriteLine (System.String format, System.Object[] arg)
+[0x00000]
+  at Test.Main () [0x00000]
+
+
+*** TEST 2 Result ***
+
+Unhandled Exception: System.ArgumentNullException: Argument cannot be null.
+  at System.String.FormatHelper (System.Text.StringBuilder result,
+IFormatProvider provider, System.String format, System.Object[] args) [0x00000]
+  at System.Text.StringBuilder.AppendFormat (IFormatProvider provider,
+System.String format, System.Object[] args) [0x00000]
+  at System.Text.StringBuilder.AppendFormat (System.String format,
+System.Object[] args) [0x00000]
+  at Test.Main () [0x00000]
+
+
+
+Expected Results:
+Null object
+ 
+Null test2 
+
+How often does this happen? 
+Always
+
+Additional Information:
+There may be other places that do formatting.  I am not familiar enough
+with .Net to say that this pattern is only in String and StringBuilder.
+
+Thanks!