Possible bug: NullReferenceException during request processing

[YaLehin]

Description

If there are simultaneous requests to an app then sometimes there is NullReferenceException accrues while creation of FilterService. The currentRequest._resourceContex parameter of the constructor is null.
This error is not stable. In most cases, it occurs after the application is started. After some number of requests, it disappears. But if you restart the application it will be again.
I tried this on macOS system and not tried on windows.
...
To reproduce:
I found this in my project, but if you take the GettingStarted example the result will be the same. Start the GettingStarted project and run simultaneous requests. (For example, for nix like system:
$ echo http://localhost:5001/api/articles http://localhost:5001/api/articles | xargs -P 10 -n1 curl
)
There will be an exception.

Environment

• Asp.Net Core 3.1
• JsonApiDotNetCore Version: v.4.0.0-alpha4 or latest master branch

[bart-degreed]

Thanks a lot for reporting this!
What JADNC version are you using?

[YaLehin]

Sorry, is JADNC abbreviation of JsonApiDotNetCore? :) If yes, then v4.0.0alpha4. I also tried the source from the master branch of this repo.

[bosk59]

I confirm, same problem on same version.
Not a small bug ... For the moment we have contourned the problem by applying an attempt/retry mechanism at front side. Not an ideal way sure...

[bart-degreed]

Serious bug indeed. I can repro this and believe I have found the root cause. Will work on a fix tomorrow.