Change properties to nullable in all places that can be returned null by the service

[fabionaspolini]

Describe the feature

I saw that primitive types have already been changed to nullable, but complex objects (such as lists and nested objects) are not marked as nullable. I would like everything that can be null to be declared as nullable for better readability in projects that already have 'enable` enabled in the csproj.

Use Case

APIGateway SDKs, LoadBalancer, Targetgroup, ECS, and many others don't support nullable complex objects.

After migrating from v3 to v4, I encountered numerous null reference issues, and solving them was a trial-and-error process. If they were marked as nullable, the compiler would have issued warnings or errors depending on the project setup.

Proposed Solution

No response

Other Information

No response

Acknowledgements

• I may be able to implement this feature request
• This feature might incur a breaking change

AWS .NET SDK and/or Package version used

AWSSDK v4+

Targeted .NET Platform

.NET Core 8

Operating System and version

Windows, Linux

[dscpinheiro]

There's been similar feedback in the V4 tracker (#3362) about this as well, and we're investigating internally what the best path forward is.

Important: We may not make changes since it would be a compiler breaking change (if you read the last few comments on the other issue you'll see why this decision was made for V4).