* terraform: refactor signature of EvalContext.InitProvisioner
Nothing was using the returned provisioners.Interface, so I simplified
the signature.
* terraform: remove provisioner-related EvalTree()s
The various Evals in eval_provisioner were removed from all callers and
replaced with straight-through code.
`NodeValidatableResource.EvalTree()` to `Execute()` was more involved. I
chose to leave the `EvalValidateResource` and `EvalValidateProvisioner`
Eval functions mostly as-is, changing the main function to `.Validate` to
make it clear that these are no longer eval nodes. Eventually I expect
to rename the file (perhaps to just Validate).
This function was previously checking for a path length greater than one
because the older path format included an always present "root" element
at the start.
We now need to check for a totally-empty list, because otherwise we fail
to add the expected prefix to the front of a path with only one element.
This also includes some adjustments to the related tests and transforms
that do not change behavior but do make the test results easier to
understand and debug.
Due to how deeply the configuration types go into Terraform Core, there
isn't a great way to switch out to HCL2 gradually. As a consequence, this
huge commit gets us from the old state to a _compilable_ new state, but
does not yet attempt to fix any tests and has a number of known missing
parts and bugs. We will continue to iterate on this in forthcoming
commits, heading back towards passing tests and making Terraform
fully-functional again.
The three main goals here are:
- Use the configuration models from the "configs" package instead of the
older models in the "config" package, which is now deprecated and
preserved only to help us write our migration tool.
- Do expression inspection and evaluation using the functionality of the
new "lang" package, instead of the Interpolator type and related
functionality in the main "terraform" package.
- Represent addresses of various objects using types in the addrs package,
rather than hand-constructed strings. This is not critical to support
the above, but was a big help during the implementation of these other
points since it made it much more explicit what kind of address is
expected in each context.
Since our new packages are built to accommodate some future planned
features that are not yet implemented (e.g. the "for_each" argument on
resources, "count"/"for_each" on modules), and since there's still a fair
amount of functionality still using old-style APIs, there is a moderate
amount of shimming here to connect new assumptions with old, hopefully in
a way that makes it easier to find and eliminate these shims later.
I apologize in advance to the person who inevitably just found this huge
commit while spelunking through the commit history.
