We now permit at most one `required_providers` block per module (except
for overrides). This prevents users (and Terraform) from struggling to
understand how to merge multiple `required_providers` configurations,
with `version` and `source` attributes split across multiple blocks.
Because only one `required_providers` block is permitted, there is no
need to concatenate version constraints and resolve them. This allows us
to simplify the structs used to represent provider requirements,
aligning more closely with other structs in this package.
This commit also fixes a semantic use-before-initialize bug, where
resources defined before a `required_providers` block would be unable to
use its source attribute. We achieve this by processing the module's
`required_providers` configuration (and overrides) before resources.
Overrides for `required_providers` work as before, replacing the entire
block per provider.
This encapsulates the logic for selecting an implied FQN for an
unqualified type name, which could either come from a local name used in
a module without specifying an explicit source for it or from the prefix
of a resource type on a resource that doesn't explicitly set "provider".
This replaces the previous behavior of just directly calling
NewDefaultProvider everywhere so that we can use a different implication
for the local name "terraform", to refer to the built-in terraform
provider rather than the stale one that's on registry.terraform.io for
compatibility with other Terraform versions.
* configs: parse provider source string during module merge
This was the smallest unit of work needed to start writing provider
source tests!
* Update configs/parser_test.go
Co-Authored-By: Alisdair McDiarmid <alisdair@users.noreply.github.com>
Renamed file.ProviderRequirements to file.RequiredProviders to match the
name of the block in the configuration. file.RequiredProviders contains
the contents of the file(s); module.ProviderRequirements contains the
parsed and merged provider requirements.
Extended decodeRequiredProvidersBlock to parse the new provider source
syntax (version only, it will ignore any other attributes).
Added some tests; swapped deep.Equal with cmp.Equal in the
terraform/module_dependencies_test.go because deep was not catching
incorrect constraints.
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.
Initially the intent here was to tease these apart a little more since
they don't really share much behavior in common in core, but in practice
it'll take a lot of refactoring to tease apart these assumptions in core
right now and so we'll keep these things unified at the configuration
layer in the interests of minimizing disruption at the core layer.
The two types are still kept in separate maps to help reinforce the fact
that they are separate concepts with some behaviors in common, rather than
the same concept.
We have a few special use-cases in Terraform where an object is
constructed from a mixture of different sources, such as a configuration
file, command line arguments, and environment variables.
To represent this within the HCL model, we introduce a new "synthetic"
HCL body type that just represents a map of values that are interpreted
as attributes.
We then export the previously-private MergeBodies function to allow the
synthetic body to be used as an override for a "real" body, which then
allows us to combine these various sources together while still retaining
the proper source location information for each individual attribute.
Since a synthetic body doesn't actually exist in configuration, it does
not produce source locations that can be turned into source snippets but
we can still use placeholder strings to help the user to understand
which of the many different sources a particular value came from.
Previously we just ported over the simple "string", "list", and "map" type
hint keywords from the old loader, which exist primarily as hints to the
CLI for whether to treat -var=... arguments and environment variables as
literal strings or as HCL expressions.
However, we've been requested before to allow more specific constraints
here because it's generally better UX for a type error to be detected
within an expression in a calling "module" block rather than at some point
deep inside a third-party module.
To allow for more specific constraints, here we use the type constraint
expression syntax defined as an extension within HCL, which uses the
variable and function call syntaxes to represent types rather than values,
like this:
- string
- number
- bool
- list(string)
- list(any)
- list(map(string))
- object({id=string,name=string})
In native HCL syntax this looks like:
variable "foo" {
type = map(string)
}
In JSON, this looks like:
{
"variable": {
"foo": {
"type": "map(string)"
}
}
}
The selection of literal processing or HCL parsing of CLI-set values is
now explicit in the model and separate from the type, though it's still
derived from the type constraint and thus not directly controllable in
configuration.
Since this syntax is more complex than the keywords that replaced it, for
now the simpler keywords are still supported and "list" and "map" are
interpreted as list(any) and map(any) respectively, mimicking how they
were interpreted by Terraform 0.11 and earlier. For the time being our
documentation should continue to recommend these shorthand versions until
we gain more experience with the more-specific type constraints; most
users should just make use of the additional primitive type constraints
this enables: bool and number.
As a result of these more-complete type constraints, we can now type-check
the default value at config load time, which has the nice side-effect of
allowing us to produce a tailored error message if an override file
produces an invalid situation; previously the result was rather confusing
because the error message referred to the original definition of the
variable and not the overridden parts.
Some of the fields in our config structs are either mandatory in primary
files or there is a default value that we apply if absent.
Unfortunately override files impose the additional constraint that we
be allowed to omit required fields (which have presumably already been
set in the primary files) and that we are able to distinguish between a
default value and omitting a value entirely.
Since most of our fields were already acceptable for override files, here
we just add some new fields to deal with the few cases where special
handling is required and a helper function to disable the "Required" flag
on attributes in a given schema.
This method wraps LoadConfigFile to load all of the .tf and .tf.json files
in a given directory and then bundle them together into a Module object.
This function also deals with the distinction between primary and override
files, first appending together the primary files in lexicographic order
by filename, and then merging in override files in the same order.
The merging behavior is not fully implemented as of this commit, and so
will be expanded in future commits.
