CA2000 ConcurrentDictionary AddOrUpdate (false positive)

[k1ll3r8e]

Analyzer package

Microsoft.CodeAnalysis.FxCopAnalyzers

Package Version

v2.9.8 (Latest)

Diagnostic ID

Example: CA2000

Repro steps

1. Using .Net Framework 4.6
2. Adding a disposable type to a ConcurrentDictionary

    private readonly ConcurrentDictionary<uint, Channel> _chs = new ConcurrentDictionary<uint, Channel>();
    
    public IChannel GetChannel(int timeout)
    {
        if (Connected)
        {
            lock (syncThreadID)
            {
                if (_threadID > C_MAX)
                {
                    _threadID = 1;
                }
                uint id = _threadID++;
                while (_chs.ContainsKey(id))
                {
                    id = _threadID++;
                }
                return _chs.AddOrUpdate(id, new Channel(this, id, timeout), (k, v) => v);
            }
        }
        return null;
    }

Expected behavior

    return _chs.AddOrUpdate(id, new Channel(this, id, timeout), (k, v) => v);

The Channel is created, added to the ConcurrentDictionary and will be returned to the caller. So the caller has to call Dispose on it's own. The Dispose implementation in the "Channel" removes it from ConcurrentDictionary. Also, disconnecting/closing/disposing the Socket, where GetChannel(int timeout) is implemented, will raise an event which cause all "Channel"s to Dispose them self. So, in any case , the CA2000 is a false positive report in this situation.

Actual behavior

    return _chs.AddOrUpdate(id, new Channel(this, id, timeout), (k, v) => v);

A CA2000 error is emitted.

[mavasani]

https://dotnet.myget.org/feed/roslyn-analyzers/package/nuget/Microsoft.CodeAnalysis.FxCopAnalyzers/2.9.9-beta1.19610.1+906398e7 should have the fix.