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.
When HCL encounters an error during expression evaluation, it annotates
its diagnostics with information about the expression that was being
evaluated and the EvalContext it was evaluated in.
This gives us enough information to show helpful hints to the user about
the final values of any reference expressions that are present in the
expression, which is very useful extra context for expressions that get
evaluated multiple times, such as:
- Any expression in a block with "count" or "for_each" set
- The sub-expressions within a "for" expression
If we get a diagnostic message that references a source range, and if the
source code for the referenced file is available, we'll show a snippet of
the source code with the source range highlighted.
At the moment we have no cache of source code, so in practice this
codepath can never be visited. Callers to format.Diagnostic will be
gradually updated in subsequent commits.
This new method showDiagnostics takes any value that would be accepted by
tfdiags.Append and renders it to the UI.
This is intended to encourage consistent handling of the different kinds
of errors and diagnostics that can be produced, and allow richer error
objects like the HCL2 diagnostics to be easily unwrapped and shown in
their full-fidelity.
Martin Atkins