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Changes links to internal/terraform in architecture.md

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@ -85,12 +85,12 @@ specified in the operation, then uses the _config loader_ to load and do
initial processing/validation of the configuration specified in the initial processing/validation of the configuration specified in the
operation. It then uses these, along with the other settings given in the operation. It then uses these, along with the other settings given in the
operation, to construct a operation, to construct a
[`terraform.Context`](https://pkg.go.dev/github.com/placeholderplaceholderplaceholder/opentf/internal/terraform#Context), [`terraform.Context`](https://pkg.go.dev/github.com/placeholderplaceholderplaceholder/opentf/internal/opentf#Context),
which is the main object that actually performs OpenTF operations. which is the main object that actually performs OpenTF operations.
The `local` backend finally calls an appropriate method on that context to The `local` backend finally calls an appropriate method on that context to
begin execution of the relevant command, such as begin execution of the relevant command, such as
[`Plan`](https://pkg.go.dev/github.com/placeholderplaceholderplaceholder/opentf/internal/terraform#Context.Plan) [`Plan`](https://pkg.go.dev/github.com/placeholderplaceholderplaceholder/opentf/internal/opentf#Context.Plan)
or or
[`Apply`](), which in turn constructs a graph using a _graph builder_, [`Apply`](), which in turn constructs a graph using a _graph builder_,
described in a later section. described in a later section.
@ -160,7 +160,7 @@ kind of arbitrary blob store.
## Graph Builder ## Graph Builder
A _graph builder_ is called by a A _graph builder_ is called by a
[`terraform.Context`](https://pkg.go.dev/github.com/placeholderplaceholderplaceholder/opentf/internal/terraform#Context) [`terraform.Context`](https://pkg.go.dev/github.com/placeholderplaceholderplaceholder/opentf/internal/opentf#Context)
method (e.g. `Plan` or `Apply`) to produce the graph that will be used method (e.g. `Plan` or `Apply`) to produce the graph that will be used
to represent the necessary steps for that operation and the dependency to represent the necessary steps for that operation and the dependency
relationships between them. relationships between them.
@ -170,7 +170,7 @@ In most cases, the
graphs each represent a specific object in the configuration, or something graphs each represent a specific object in the configuration, or something
derived from those configuration objects. For example, each `resource` block derived from those configuration objects. For example, each `resource` block
in the configuration has one corresponding in the configuration has one corresponding
[`GraphNodeConfigResource`](https://pkg.go.dev/github.com/placeholderplaceholderplaceholder/opentf/internal/terraform#GraphNodeConfigResource) [`GraphNodeConfigResource`](https://pkg.go.dev/github.com/placeholderplaceholderplaceholder/opentf/internal/opentf#GraphNodeConfigResource)
vertex representing it in the "plan" graph. (OpenTF Core uses terminology vertex representing it in the "plan" graph. (OpenTF Core uses terminology
inconsistently, describing graph _vertices_ also as graph _nodes_ in various inconsistently, describing graph _vertices_ also as graph _nodes_ in various
places. These both describe the same concept.) places. These both describe the same concept.)
@ -187,23 +187,23 @@ graph from the set of changes described in the plan that is being applied.
The graph builders all work in terms of a sequence of _transforms_, which The graph builders all work in terms of a sequence of _transforms_, which
are implementations of are implementations of
[`terraform.GraphTransformer`](https://pkg.go.dev/github.com/placeholderplaceholderplaceholder/opentf/internal/terraform#GraphTransformer). [`terraform.GraphTransformer`](https://pkg.go.dev/github.com/placeholderplaceholderplaceholder/opentf/internal/opentf#GraphTransformer).
Implementations of this interface just take a graph and mutate it in any Implementations of this interface just take a graph and mutate it in any
way needed, and so the set of available transforms is quite varied. Some way needed, and so the set of available transforms is quite varied. Some
important examples include: important examples include:
* [`ConfigTransformer`](https://pkg.go.dev/github.com/placeholderplaceholderplaceholder/opentf/internal/terraform#ConfigTransformer), * [`ConfigTransformer`](https://pkg.go.dev/github.com/placeholderplaceholderplaceholder/opentf/internal/opentf#ConfigTransformer),
which creates a graph vertex for each `resource` block in the configuration. which creates a graph vertex for each `resource` block in the configuration.
* [`StateTransformer`](https://pkg.go.dev/github.com/placeholderplaceholderplaceholder/opentf/internal/terraform#StateTransformer), * [`StateTransformer`](https://pkg.go.dev/github.com/placeholderplaceholderplaceholder/opentf/internal/opentf#StateTransformer),
which creates a graph vertex for each resource instance currently tracked which creates a graph vertex for each resource instance currently tracked
in the state. in the state.
* [`ReferenceTransformer`](https://pkg.go.dev/github.com/placeholderplaceholderplaceholder/opentf/internal/terraform#ReferenceTransformer), * [`ReferenceTransformer`](https://pkg.go.dev/github.com/placeholderplaceholderplaceholder/opentf/internal/opentf#ReferenceTransformer),
which analyses the configuration to find dependencies between resources and which analyses the configuration to find dependencies between resources and
other objects and creates any necessary "happens after" edges for these. other objects and creates any necessary "happens after" edges for these.
* [`ProviderTransformer`](https://pkg.go.dev/github.com/placeholderplaceholderplaceholder/opentf/internal/terraform#ProviderTransformer), * [`ProviderTransformer`](https://pkg.go.dev/github.com/placeholderplaceholderplaceholder/opentf/internal/opentf#ProviderTransformer),
which associates each resource or resource instance with exactly one which associates each resource or resource instance with exactly one
provider configuration (implementing provider configuration (implementing
[the inheritance rules](https://www.placeholderplaceholderplaceholder.io/docs/language/modules/develop/providers.html)) [the inheritance rules](https://www.placeholderplaceholderplaceholder.io/docs/language/modules/develop/providers.html))
@ -217,7 +217,7 @@ builder uses a different subset of these depending on the needs of the
operation that is being performed. operation that is being performed.
The result of graph building is a The result of graph building is a
[`terraform.Graph`](https://pkg.go.dev/github.com/placeholderplaceholderplaceholder/opentf/internal/terraform#Graph), which [`terraform.Graph`](https://pkg.go.dev/github.com/placeholderplaceholderplaceholder/opentf/internal/opentf#Graph), which
can then be processed using a _graph walker_. can then be processed using a _graph walker_.
## Graph Walk ## Graph Walk
@ -229,13 +229,13 @@ itself is implemented in
(where "DAG" is short for [_Directed Acyclic Graph_](https://en.wikipedia.org/wiki/Directed_acyclic_graph)), in (where "DAG" is short for [_Directed Acyclic Graph_](https://en.wikipedia.org/wiki/Directed_acyclic_graph)), in
[`AcyclicGraph.Walk`](https://pkg.go.dev/github.com/placeholderplaceholderplaceholder/opentf/internal/dag#AcyclicGraph.Walk). [`AcyclicGraph.Walk`](https://pkg.go.dev/github.com/placeholderplaceholderplaceholder/opentf/internal/dag#AcyclicGraph.Walk).
However, the "interesting" OpenTF walk functionality is implemented in However, the "interesting" OpenTF walk functionality is implemented in
[`terraform.ContextGraphWalker`](https://pkg.go.dev/github.com/placeholderplaceholderplaceholder/opentf/internal/terraform#ContextGraphWalker), [`terraform.ContextGraphWalker`](https://pkg.go.dev/github.com/placeholderplaceholderplaceholder/opentf/internal/opentf#ContextGraphWalker),
which implements a small set of higher-level operations that are performed which implements a small set of higher-level operations that are performed
during the graph walk: during the graph walk:
* `EnterPath` is called once for each module in the configuration, taking a * `EnterPath` is called once for each module in the configuration, taking a
module address and returning a module address and returning a
[`terraform.EvalContext`](https://pkg.go.dev/github.com/placeholderplaceholderplaceholder/opentf/internal/terraform#EvalContext) [`terraform.EvalContext`](https://pkg.go.dev/github.com/placeholderplaceholderplaceholder/opentf/internal/opentf#EvalContext)
that tracks objects within that module. `terraform.Context` is the _global_ that tracks objects within that module. `terraform.Context` is the _global_
context for the entire operation, while `terraform.EvalContext` is a context for the entire operation, while `terraform.EvalContext` is a
context for processing within a single module, and is the primary means context for processing within a single module, and is the primary means
@ -287,20 +287,20 @@ implementation can take any action against the `EvalContext`.
The implementation of `terraform.EvalContext` used in real processing The implementation of `terraform.EvalContext` used in real processing
(as opposed to testing) is (as opposed to testing) is
[`terraform.BuiltinEvalContext`](https://pkg.go.dev/github.com/placeholderplaceholderplaceholder/opentf/internal/terraform#BuiltinEvalContext). [`terraform.BuiltinEvalContext`](https://pkg.go.dev/github.com/placeholderplaceholderplaceholder/opentf/internal/opentf#BuiltinEvalContext).
It provides coordinated access to plugins, the current state, and the current It provides coordinated access to plugins, the current state, and the current
plan via the `EvalContext` interface methods. plan via the `EvalContext` interface methods.
In order to be executed, a vertex must implement In order to be executed, a vertex must implement
[`terraform.GraphNodeExecutable`](https://pkg.go.dev/github.com/placeholderplaceholderplaceholder/opentf/internal/terraform#GraphNodeExecutable), [`terraform.GraphNodeExecutable`](https://pkg.go.dev/github.com/placeholderplaceholderplaceholder/opentf/internal/opentf#GraphNodeExecutable),
which has a single `Execute` method that handles. There are numerous `Execute` which has a single `Execute` method that handles. There are numerous `Execute`
implementations with different behaviors, but some prominent examples are: implementations with different behaviors, but some prominent examples are:
* [NodePlannableResource.Execute](https://pkg.go.dev/github.com/placeholderplaceholderplaceholder/opentf/internal/terraform#NodePlannableResourceInstance.Execute), which handles the `plan` operation. * [NodePlannableResource.Execute](https://pkg.go.dev/github.com/placeholderplaceholderplaceholder/opentf/internal/opentf#NodePlannableResourceInstance.Execute), which handles the `plan` operation.
* [`NodeApplyableResourceInstance.Execute`](https://pkg.go.dev/github.com/placeholderplaceholderplaceholder/opentf/internal/terraform#NodeApplyableResourceInstance.Execute), which handles the main `apply` operation. * [`NodeApplyableResourceInstance.Execute`](https://pkg.go.dev/github.com/placeholderplaceholderplaceholder/opentf/internal/opentf#NodeApplyableResourceInstance.Execute), which handles the main `apply` operation.
* [`NodeDestroyResourceInstance.Execute`](https://pkg.go.dev/github.com/placeholderplaceholderplaceholder/opentf/internal/terraform#EvalWriteState), which handles the main `destroy` operation. * [`NodeDestroyResourceInstance.Execute`](https://pkg.go.dev/github.com/placeholderplaceholderplaceholder/opentf/internal/opentf#EvalWriteState), which handles the main `destroy` operation.
A vertex must complete successfully before the graph walk will begin evaluation A vertex must complete successfully before the graph walk will begin evaluation
for other vertices that have "happens after" edges. Evaluation can fail with one for other vertices that have "happens after" edges. Evaluation can fail with one
@ -367,7 +367,7 @@ known when the main graph is constructed, but become known while evaluating
other vertices in the main graph. other vertices in the main graph.
This special behavior applies to vertex objects that implement This special behavior applies to vertex objects that implement
[`terraform.GraphNodeDynamicExpandable`](https://pkg.go.dev/github.com/placeholderplaceholderplaceholder/opentf/internal/terraform#GraphNodeDynamicExpandable). [`terraform.GraphNodeDynamicExpandable`](https://pkg.go.dev/github.com/placeholderplaceholderplaceholder/opentf/internal/opentf#GraphNodeDynamicExpandable).
Such vertices have their own nested _graph builder_, _graph walk_, Such vertices have their own nested _graph builder_, _graph walk_,
and _vertex evaluation_ steps, with the same behaviors as described in these and _vertex evaluation_ steps, with the same behaviors as described in these
sections for the main graph. The difference is in which graph transforms sections for the main graph. The difference is in which graph transforms