Computed attributes

Hey everyone,

Is computed attribute always unknown in plan if user doesn’t specify some value for it (if the attribute is also optional)? If so, it means that a provider has to “guess” a correct value for the attribute in plan modifier, otherwise Terraform outputs non-empty plan when there is no change in configuration (due to unknown value of the computed attribute). And if the guess is wrong, Terraform reports an error in the provider (Error: Provider produced inconsistent result after apply).

Do I miss something?

Kind regards,
Dmitry