Why default attribute must also be computed?

Terraform
1

I’m using the terraform plugin framework.

Here is a simplified schema:

func (t *T) Schema(_ context.Context, _ resource.SchemaRequest, resp *resource.SchemaResponse) {
    resp.Schema = return schema.Schema{
      "name": schema.StringAttribute{
                Optional: true,
                Default:  stringdefault.StaticString("john_doe"),
            },

    }
}

When I do terraform apply I get this error:

│ Error: Failed to load plugin schemas
│
│ Error while loading schemas for plugin components: Failed to obtain provider schema: Could not load the schema for provider my_provider: failed to retrieve schema from provider
│ "my_provider": Schema Using Attribute Default For Non-Computed Attribute: Attribute "name" must be computed when using default. This is an issue with the provider and should be
│ reported to the provider developers...

Why do attributes with a default value have to be computed ?

2

Hi @picavoh.mobijaf

Terraform has no concept of default values in a resource configuration, and initially only has access to the value as written in the config file. Following the resource lifecycle rules, in order for a provider to change a null configuration value during the plan it must be marked as computed. A default therefore is really just a computed value which returns a known value during the plan, as opposed to an unknown value which will be filled in during apply.