RFR: JDK-8319120: Unbound ScopedValue.get() throws the wrong exception [v2]

[Alan Bateman]

On Mon, 30 Oct 2023 17:16:54 GMT, Andrew Haley <aph at openjdk.org> wrote:

>> The bug here is a thinko in `ScopedValue.scopedValueBindings()`.
>> 
>> If the JVM runs out of resources, we throw a `VirtualMachineError`. Running out of resources can happen at almost any time, and can happen while `ScopedValue`'s internal structures are being modified, leaving them in an inconsistent state. We detect when a `VirtualMachineError` happens and walk the stack to find the most-recent set of `ScopedValue` bindings.
>> 
>> When we crate a new `Thread`, we push a sentinel frame onto the stack that we can find in the case that we threw a `VirtualMachineError`. Threads created by the native invocation interface (rather than by Java threads) don't have that sentinel, so a search for it returns null. Therefore, in the rare cases where we have to do a stack walk, we must check for both `NEW_THREAD_BINDINGS` (the sentinel) and `null`. We weren't doing that, we were only checking for null.
>
> Andrew Haley has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Review feedback

Marked as reviewed by alanb (Reviewer).

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PR Review: https://git.openjdk.org/jdk/pull/16422#pullrequestreview-1705767019