Bug 28134 - System.Text.EncoderFallbackException inconsistent initial state compared to .Net
Summary: System.Text.EncoderFallbackException inconsistent initial state compared to .Net
Status: RESOLVED FIXED
Alias: None
Product: Class Libraries
Classification: Mono
Component: mscorlib ()
Version: unspecified
Hardware: PC Windows
: --- normal
Target Milestone: Untriaged
Assignee: Bugzilla
URL:
Depends on:
Blocks:
 
Reported: 2015-03-17 16:46 UTC by nader
Modified: 2015-03-30 09:27 UTC (History)
2 users (show)

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

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Status:
RESOLVED FIXED

Description nader 2015-03-17 16:46:47 UTC
System.Text.EncoderFallbackException has an incorrect/inconsistent initial state compared to its implementation in .Net 4.5. The first inconsistency is that the index property is set to -1, which is  initialized to 0 in .Net.
This property is explicitly set to -1 in the mono source code which can be found in here:

https://github.com/mono/mono/blob/mono-3.10.0-branch/mcs/class/corlib/System.Text/EncoderFallbackException.cs#L68

Another inconsistency is the exception's message which is different between .Net and mono.

To reproduce this issue, run the following code snippet:

System.Text.EncoderFallbackException v0 =  new System.Text.EncoderFallbackException();
System.Int32 index = v0.Index ;
System.String message = v0.Message;
Console.WriteLine(index);
Console.WriteLine(message);

mono output:
-1
"Exception of type 'System.Text.EncoderFallbackException' was thrown."

.Net output:
0
"Value does not fall within the expected range."

The code snippet above was ran using .Net 4.5 and mono 3.3.0. The same issue happens when running the code in Xamarin android and comparing the result with a Windows Phone 8.1 project.

Additional Build Environment info:
Xamarin.Android Version: 4.16.0 (Business Edition)
Java SDK: C:\Program Files (x86)\Java\jdk1.6.0_39
Comment 1 nader 2015-03-17 16:50:45 UTC
The same issue appears for System.Text.DecoderFallbackException which appears here:

https://github.com/mono/mono/blob/mono-3.10.0-branch/mcs/class/corlib/System.Text/DecoderFallbackException.cs#L60
Comment 2 Marek Safar 2015-03-30 09:27:45 UTC
Fixed in mono 4.0