Bug 2023 - System.Uri.Equals(object) should not throw an exception (when passed an non-uri-string)
Summary: System.Uri.Equals(object) should not throw an exception (when passed an non-u...
Alias: None
Product: Class Libraries
Classification: Mono
Component: System ()
Version: 2.10.x
Hardware: PC Linux
: --- normal
Target Milestone: Untriaged
Assignee: Bugzilla
Depends on:
Reported: 2011-11-14 07:59 UTC by Christian Klauser
Modified: 2011-11-24 08:23 UTC (History)
3 users (show)

Is this bug a regression?: ---
Last known good build:

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Description Christian Klauser 2011-11-14 07:59:45 UTC
The implementation of the Equals method on Uri objects (System.Uri.Equals(System.Object)) throws an exception when passed a one character string.

Consider the following program:

public class Program
        public static void Main(string[] args)
                var uri = new System.Uri("http://xkcd.com");

Expected result: Prints "False"
Actual result:
Unhandled Exception: System.UriFormatException: Absolute URI is too short
  at System.Uri.Parse (UriKind kind, System.String uriString) [0x00027] in /usr/src/redhat/BUILD/mono-2.10.2/mcs/class/System/System/Uri.cs:1342
  at System.Uri.ParseUri (UriKind kind) [0x00000] in /usr/src/redhat/BUILD/mono-2.10.2/mcs/class/System/System/Uri.cs:1199
  at System.Uri..ctor (System.String uriString, Boolean dontEscape) [0x00059] in /usr/src/redhat/BUILD/mono-2.10.2/mcs/class/System/System/Uri.cs:219
  at System.Uri..ctor (System.String uriString) [0x00000] in <filename unknown>:0
  at System.Uri.Equals (System.Object comparant) [0x00024] in /usr/src/redhat/BUILD/mono-2.10.2/mcs/class/System/System/Uri.cs:846
  at Program.Main (System.String[] args) [0x0000b] in /home/ec2-user/uri-equals-bug.cs:6

According to microsoft's documentation [1] "Implementations of Equals must not throw exceptions."
In my particular case, System.Web.Mvc.DefaultModelBinder.GetPropertyValue (part of ASP.NET MVC3) makes use of System.Uri.Equals(System.Object) when I bind against a model object with a System.Uri field. So short of not using the library's data binding facilities or changing my model, there is no easy workaround.

[1]: http://msdn.microsoft.com/en-us/library/bsc2ak47.aspx 
Section "Remarks"
Comment 1 Marek Safar 2011-11-24 08:23:02 UTC
Fixed in master