Compatibility Issue with MongoDB Driver in .NET 8 AOT Environment

Working with Data Drivers
1

Hello MongoDB Community,

I am currently working on a project using .NET 8 and am attempting to leverage the Ahead-Of-Time (AOT) compilation feature. However, I’ve encountered a compatibility issue with the MongoDB driver, specifically when using AOT.

The error message I’m receiving is as follows:

Unhandled Exception: System.MissingMethodException: No suitable constructor found for serializer type: 'MongoDB.Bson.Serialization.Serializers.StringSerializer'.
   at MongoDB.Bson.Serialization...
   ... [remainder of stack trace] ...
   at WebApplication2!<BaseAddress>+0xcde883

This exception suggests that there might be an issue with the constructor selection for the StringSerializer in the AOT context. It seems to be a problem with reflection or dynamic code generation, which are known limitations of AOT environments.

I am keen to know if there is an existing or planned update for the MongoDB driver that will address this compatibility issue with .NET 8 AOT. Additionally, if anyone has encountered a similar problem or has suggestions for a workaround, your insights would be greatly appreciated.

Thank you for your time and assistance.

Best regards,
Marcelo

2

Hello @Marcelo_Gondim

Yes this a known issue, we are tracking this in CSHARP-4840.

The workaround would be opting-out the driver from trimming.
One way to do so is setting TrimMode to partial and specifying all trimmed assemblies manually by TrimmableAssembly item.

1 Like
3

Hi Boris, Is there any progress regarding this task “CSHARP-4840”.

4

Hi @Asli,
Unfortunately we don’t have a target date for supporting trimming yet. Please follow the ticket in Jira for further updates.

5

Hi Boris,

As we are now approaching the release of .Net 10 it’s becoming quite an issue having no trimming support in the MongoDb driver. Looking at the ticket it hasn’t been updated since it was created. Is there any word on when this might be looked at?

Thanks.

6

Hi @Nigel_Anderton
We are planning to tackle that in the upcoming quarter.