System.NullReferenceException in GetCurrentOrderAsync (v16)

[JohnFunnell-MRM]

Which component is this issue related to?

Umbraco Commerce (Core)

Which Umbraco Commerce version are you using? (Please write the exact version, example: 10.1.0)

16.3.1

Bug summary

After upgrading to v16 of Umbraco and Commerce, some users are experiencing an error when we try to get or create their current order.

Below is the stack trace we're seeing in the logs:

System.NullReferenceException: Object reference not set to an instance of an object.
   at Umbraco.Commerce.Infrastructure.Resiliency.PollyExecutionStrategyBase.ExecuteAsync[TResult](Func`2 operation, Func`2 verifySucceeded, CancellationToken cancellationToken)
   at Umbraco.Commerce.Core.Services.OrderService.PerformGetStateAsync(Guid id)
   at Umbraco.Commerce.Core.Cache.DefaultEntityStatePolicyCache`2.GetAsync(TId id, Func`2 performGetAsync, Func`2 performGetAllAsync)
   at Umbraco.Commerce.Core.Services.OrderService.GetOrderAsync(Guid id)
   at Umbraco.Commerce.Core.Session.SessionManager.<>c__DisplayClass13_0.<<GetCurrentOrderAsync>b__0>d.MoveNext()
--- End of stack trace from previous location ---
   at Umbraco.Commerce.Core.Session.SessionManager.WithSessionStoreAsync[T](Guid storeId, Func`2 action)
   at Umbraco.Commerce.Core.Session.SessionManager.GetCurrentOrderAsync(Guid storeId)

Specifics

No response

Steps to reproduce

It's hard to reproduce this as it only happens to some users. We're trying to obtain more information to help identify the conditions when this happens.

Expected result / actual result

No response

Dependencies

No response

[mattbrailsford]

Yea, it's a bit hard to go off this at the moment.

From the stack trace it would appear it got an cart from the session and attempted to retrieve it.

Maybe if you provide some details about your install? Is it load balanced or anything? do you have any customizations?

[JohnFunnell-MRM]

It's an Umbraco cloud project and the only customisation is a OrderLineCalculator and a ProductAdaptor.

This doesn't happen for anyone internally so it's hard for us to give more detail. A few customers have raised the issue with the site so we're trying to gather more information from them.

Is there some logging I can put in to help? For example, what's the best way to get the customer reference?

[mattbrailsford]

The fact it's coming from PerformGetStateAsync is a bit strange because there isn't much in there that could be null. The best I can think is that it's having problems loading the order state from the DB. For this I'd probably try and do some logging to see which orders specifically this is happening on and then lookup the data in the database to see if something is null that shouldn't be.

[mattbrailsford]

@JohnFunnell-MRM did you manage to find any further info?

[JohnFunnell-MRM]

Not yet. I'm trying to figure out how I can get the order reference from users who have this problem without going through the GetCurrentOrderAsync method as that throws an exception.

I thought I posted a comment on here last week but it looks like it didn't go through for some reason.