Provide a way to verify which thread owns a lock

[vsfeedback]

This issue has been moved from a ticket on Developer Community.

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On the new Lock Class introduced on .NET 9.0 preview, we have a property (IsHeldByCurrentThread) that allows us to check whether the lock is being held by the current thread or not: https://learn.microsoft.com/en-us/dotnet/api/system.threading.lock?view=net-9.0

However, if a lock is being hold by a different thread, it becomes difficult to determine which thread holds the lock. I understand that this isn't impossible to achieve, since Win32's critical section has an internal member that tells the user that information.

Having this supposed new property that tells us the current Id of the thread that's holding the lock could make software engineer's lives easier, as it would improve traceability when debugging code.

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Original Comments

Feedback Bot on 5/10/2024, 10:36 PM:

(private comment, text removed)

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[kouvel]

For heap dump diagnostics, #101192 tracks info about threads waiting on a lock and provides info about which thread holds the lock.

Lock tracks some thread ID in a field (managed thread ID in NativeAOT, and OS thread ID elsewhere). For on-the-fly traceability or temporary purposes that could be used.

If there were to be an API to expose it, since managed thread IDs are opaque, there probably would need to also be a way to translate one to a Thread object and a way to obtain the corresponding OS thread ID. Could be considered if there's a need, please open an API suggestion with more details in that case.