Previously we had the evaluate methods accept directly an
addrs.InstanceKey and had our evaluator infer a suitable value for
count.index for it, but that prevents us from setting the index to be
unknown in the validation scenario where we may not be able to predict
the number of instances yet but we still want to be able to check that
the configuration block is type-safe for all possible count values.
To achieve this, we separate the concern of deciding on a value for
count.index from the concern of evaluating it, which then allows for
other implementations of this in future. For the purpose of this commit
there is no change in behavior, with the count.index value being populated
whenever the instance key is a number.
This commit does a little more groundwork for the future implementation
of the for_each feature (which'll support each.key and each.value) but
still doesn't yet implement it, leaving it just stubbed out for the
moment.
Previously we would just retain an empty InstanceState in this case, but
now that we must enumerate all of the available instances during
expression evaluation it's important that we be able to recognize
instances that have been deleted.
On the initial pass here I reached a faulty conclusion about what from
the new world should shim into a NewInstanceInfo, based on a poor read
of existing code.
It actually _should've_ been based on an absolute instance after all,
as evidenced by the expected result of TestContext2Refresh_targetedCount.
Therefore the signature is changed here, and all of the callers (which,
in retrospect, were all holding a full instance address anyway!) are
updated to that new signature.
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.
The fact that we clean up data source state by applying a "destroy" action
for them is an implementation detail, and so should not be visible to
outside callers or to the user.
Signalling these as real destroys creates confusion for users because
they see Terraform say things like:
data.template_file.foo: Refreshing state..."
...which, to an understandably-nervous sysadmin, might make them suspect
that the underlying object was deleted, rather than just Terraform's
record of it.
A race when accessing Provisioner.RawConfig can cause unexpected output
for provisioners that interpolate variables. Use RawConfig.Copy which
needs to acquire the RawConfig mutex to get the values.
Fixes#8890
