[.NET 7 Preview 2]Sporadic ArgumentException from ThreadLocal initialization #67491
Description
Description
My unit tests accidentally revealed an issue in ThreadLocal<T>, more precisely in its IdManager.GetId method:
System.ArgumentException: An item with the same key has already been added. Key: 0
at System.Collections.Generic.Dictionary`2.TryInsert(TKey key, TValue value, InsertionBehavior behavior)
at System.Threading.ThreadLocal`1.IdManager.GetId(Boolean trackAllValues)
at System.Threading.ThreadLocal`1.Initialize(Func`1 valueFactory, Boolean trackAllValues)
at System.Collections.Concurrent.ConcurrentBag`1..ctor(IEnumerable`1 collection)
Reproduction Steps
I apologize for not being able to provide a minimal repro. I tried to create multiple ConcurrentBag<T> instances in a cycle (as you can see in the call stack the exception comes from its constructor, which initializes a ThreadLocal<int> instance) but I could not reproduce the error this way.
But feel free to fork the Net7Test branch of my repo and execute the tests of the KGySoft.CoreLibraries.UnitTest project.
When executing all of the tests there is a good chance that the SerializeSimpleGenericCollections test case throws the exception with the call stack above. Note that by executing this test alone it will always be green.
Expected behavior
Creating a new ConcurrentBag<T> instance should not throw an exception.
Actual behavior
Creating a new ConcurrentBag<T> may sometimes throw the mentioned exception.
Regression?
No response
Known Workarounds
No response
Configuration
.NET version: 7.0.100-preview.2.22153.17
Other information
No response