JIT Error?

Did you know? Since BC 22 we are facing an issue which we call "JIT Error".

If you run Rec.CalcFields on a page to "calculate" a blob, next time you change the Record you will get the following error:

You can easily reproduce that issue with our repo:

https://github.com/byndit/Debug-JIT-Error#readme

Wait... JIT?

Yes! JIT means Just-In-Time.

"When a record is loaded as a partial record, the obvious question is: What happens when accessing a field that hasn't been selected for loading?

The answer is JIT loading. The platform, in such a case, does an implicit Get on the record and loads out the missing field."

Read more using partial records on https://learn.microsoft.com/en-us/dynamics365/business-central/dev-itpro/developer/devenv-partial-records

This error occurs by using the following Version:

Our Test Scenarios:

• Test Page 1:

  • OnAfterGetRecord -> Rec.CalcFields -> Error

• Test Page 2:

  • OnAfterGetRecord -> NewRec = Rec -> NewRec.CalcFields -> No Error

• Test Page 3:

  • SelectLatestVersion in OnAction trigger -> OnAfterGetRecord -> Rec.CalcFields -> No Error

• Test Page 4:

  • Blob Field shown on the Page -> OnAfterGetRecord -> Rec.CalcFields -> No Error

• Test Page 5:

  • Blob Field hidden on the Page -> OnAfterGetRecord -> Rec.CalcFields -> No Error

First Test:

To reproduce the error in the first test page 62001:

1. Open the page
2. Add some entries as shown:

3. Mark the second or third entry
4. Click on “Run Action” (two times):
   • First time: Test Bool will be switched to “true”
   • Second time: Error

Second Test:

To reproduce the error in the first test page 62001:

1. Reopen the page after you got the error
2. The second entry (if selected before) has Test Bool set to true now:

3. Mark the second entry
4. Click on “Run Action”
   • The error will come up directly and the page will be closed
   • Then you can’t start the page again until you clean your cache