"/var/task directory is missing the required .deps.json file" error started happening on previously deployed SAM stack

[snowberry-clearwing]

When I attempted to redeploy an updated Lambda function with SAM, I started receiving the error "Error: .NET binaries for Lambda function are not correctly installed in the /var/task directory of the image when the image was built. The /var/task directory is missing the required .deps.json file." I reverted the changes and tried to redeploy an older version with no avail. I checked the output of the package and noted the .dep.json file was not in the root as required. I am not aware of updating anything myself, however what could be the reason this previously worked but not any longer? I also found when I manually packaged the Lambda with dotnet lambda package the .deps.json was in the correct location and I was able to manually upload the package.

[normj]

Can you make sure in your project file it has the following property in a PropertyGroup
true

The dotnet lambda package command will always set the /:GenerateRuntimeConfigurationFiles=true command line property when doing the package.
By default the *.deps.json file is not created by the dotnet publish command for class libraries and this property force it to be created.
Answer:

[Soundman32]

Which property should be set to true? The answer just says true.

[normj]

The GenerateRuntimeConfigurationFiles property. Here is an example from the .NET Lambda blueprints https://github.com/aws/aws-lambda-dotnet/blob/master/Blueprints/BlueprintDefinitions/vs2022/EmptyFunction/template/src/BlueprintBaseName.1/BlueprintBaseName.1.csproj#L6

[SurajNarang]

I do have this set to true already <GenerateRuntimeConfigurationFiles>true</GenerateRuntimeConfigurationFiles>
However, I still get the error of the following:
Error: .NET binaries for Lambda function are not correctly installed in the /var/task directory of the image when the image was built. The /var/task directory is missing the required .deps.json file.

Any suggestions on what else I can check please

[normj]

I have seen this error before if you have the function handler set to class library style <assembly>::<type>::<method> but the code is build as an executable including a main. In the executable assembly scenario the function handler should be set to just the assembly name.

[nalinjax]

Thanks NormJ. For me setting the Handler (name) to the name of the assembly generated during publishing to AWS is what solved the issue.
I am using Visual Studio 2022. Nowhere else did I read that building with the new .NET 8 AOT configuration for a Lambda function results in this requirement. I was used to the previous :::: format.
Thank you for sharing your knowledge!

[github-actions[bot]]

Hello! Reopening this discussion to make it searchable.

[matlaver]

The other thing to check is make sure you've run sam build first.