ThreadsafeTypeKeyHashTable.VolatileWrite missing nullable declaration for value parameter

[pikpok-lihhern]

When trying to build MessagePack within Unity, I noticed that the latest release (2.5.140) did not enable nullable reference type via the csc.rsp file. So I manually added them to get rid of the noisy warnings only to get a warning:

ThreadsafeTypeKeyHashTable.cs(214,9): warning CS8824: Parameter 'location' must have a non-null value when exiting because parameter 'value' is non-null.

The problem:
private static void VolatileWrite([NotNullIfNotNull("value")] ref Entry? location, Entry value)
Entry value is not nullable.

The fix is:
private static void VolatileWrite([NotNullIfNotNull("value")] ref Entry? location, Entry? value)
Flag it nullable: Entry? value.

P.S. Perhaps for future release, it would also be good to include the csc.rcp file alongside all asmdef files to enable nullable reference type.

[AArnott]

Thanks for the report. I suppose this will be solved in our upcoming major release because #1734 will avoid unity having to compile messagepack source code any more.

[pikpok-lihhern]

Cool. Yes, that sounds great. Also, I'm looking forward to the upcoming roslyn code generator. Getting rid of MPC dependency is great!