Previously we were using the experimental HCL 2 repository, but now we'll
shift over to the v2 import path within the main HCL repository as part of
actually releasing HCL 2.0 as stable.
This is a mechanical search/replace to the new import paths. It also
switches to the v2.0.0 release of HCL, which includes some new code that
Terraform didn't previously have but should not change any behavior that
matters for Terraform's purposes.
For the moment the experimental HCL2 repository is still an indirect
dependency via terraform-config-inspect, so it remains in our go.sum and
vendor directories for the moment. Because terraform-config-inspect uses
a much smaller subset of the HCL2 functionality, this does still manage
to prune the vendor directory a little. A subsequent release of
terraform-config-inspect should allow us to completely remove that old
repository in a future commit.
This now uses the HCL2 parser and evaluator APIs and evaluates in terms
of a new-style *lang.Scope, rather than the old terraform.Interpolator
type that is no longer functional.
The Context.Eval method used here behaves differently than the
Context.Interpolater method used previously: it performs a graph walk
to populate transient values such as input variables, local values, and
output values, and produces its scope in terms of the result of that
graph walk. Because of this, it is a lot more robust than the prior method
when asked to resolve references other than those that are persisted
in the state.
