Bug 25585 - ConcurrentDictionary implementation of Remove(KeyValuePair<TKey, TValue>) incorrect
Summary: ConcurrentDictionary implementation of Remove(KeyValuePair<TKey, TValue>) inc...
Alias: None
Product: Class Libraries
Classification: Mono
Component: mscorlib ()
Version: unspecified
Hardware: PC Linux
: --- normal
Target Milestone: Untriaged
Assignee: Bugzilla
Depends on:
Reported: 2014-12-23 05:31 UTC by Josip Bakic
Modified: 2014-12-24 03:42 UTC (History)
2 users (show)

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

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Description Josip Bakic 2014-12-23 05:31:05 UTC
The method Remove from the interface ICollection<KeyValuePair<TKey, TValue>> is implemented differently in Mono than on the .NET Framework. Namely, the .NET method will also compare the values and remove only if the value is equal (.NET reference source available at: http://referencesource.microsoft.com/#mscorlib/system/Collections/Concurrent/ConcurrentDictionary.cs,1304 ). The Mono implementation just checks the key.

Although this safe remove trick seems a little hacky (it is not documented in MSDN library documentation, there is only a 3 yr old blog post on MSDN describing this, and the method is actually privately implemented so you really have to know this is there to be able to use it...), it is incredibly useful since otherwise removal from the dictionary, concurrent with adding to and updating it, is unsafe and requires using a lock in a lot of cases.

Also, this issue is very similar to the already resolved issue #16990, related to method Contains from the same interface. These two should probably behave similarly.
Comment 1 Marek Safar 2014-12-24 03:42:27 UTC
master mono uses reference source concurrent collections implementation