Bug 29517 - TryUpdate for ConcurrentDictionary behaves differently from .NET when comparison value is null
Summary: TryUpdate for ConcurrentDictionary behaves differently from .NET when compari...
Alias: None
Product: Class Libraries
Classification: Mono
Component: System ()
Version: 3.10.0
Hardware: PC Linux
: --- normal
Target Milestone: Untriaged
Assignee: Bugzilla
Depends on:
Reported: 2015-04-29 04:45 UTC by Narinder
Modified: 2015-04-29 09:13 UTC (History)
2 users (show)

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

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Description Narinder 2015-04-29 04:45:38 UTC
The following piece of code :

        static void Main(string[] args)
                ConcurrentDictionary<string, string> theDict = new ConcurrentDictionary<string, string>();

                string nullString = null;
                theDict.GetOrAdd("key", nullString);
                theDict.TryUpdate("key", "hello", null);

            catch (Exception e)

Throws an exception on Mono :
Object reference not set to an instance of an object

on .NET 4.0 no exception is thrown.

Mono Setup is :
Mono JIT compiler version 3.10.0 ((no/633e444 Wed Nov 12 15:36:54 GMT 2014)
Copyright (C) 2002-2014 Novell, Inc, Xamarin Inc and Contributors. www.mono-project.com
	TLS:           __thread
	SIGSEGV:       altstack
	Notifications: epoll
	Architecture:  amd64
	Disabled:      none
	Misc:          softdebug 
	LLVM:          supported, not enabled.
	GC:            sgen

On Debian
Comment 1 Marek Safar 2015-04-29 07:05:29 UTC
Fixed in Mono 4.0
Comment 2 Narinder 2015-04-29 09:13:20 UTC
Thanks !