I'd like to optionally declare an environment variable within vercel_deployment using a ternary/conditional expression by either setting a string or null.
For example:

environment = {
    MY_VAR = terraform.workspace == "default" ? "value" : null
}

This however throws an unhandled null value exception.

The only workaround right now is to instead set an empty string:

environment = {
    MY_VAR = terraform.workspace == "default" ? "value" : ""
}

I believe it would be a good addition also allow null values, and just ignore the environment entry then.