Apply suggestions from code review

Co-authored-by: Sarah French <15078782+SarahFrench@users.noreply.github.com>

Author: dsa0x

internal/plans/plan.go

@@ -171,7 +171,7 @@ type Plan struct {
 	FunctionResults []lang.FunctionResultHash
 
 	// PolicyResults stores the results of policy evaluations that were performed
-	// while making this plan.
+	// while making this plan. These policy results will not be serialized in the plan file.
 	PolicyResults *PolicyResults
 }
 

internal/terraform/context_apply.go

@@ -50,10 +50,12 @@ type ApplyOpts struct {
 	AllowRootEphemeralOutputs bool
 
 	// Locks is a read-only snapshot of provider locks (from the dependency lock
-	// file).
+	// file). This is required by policy evaluations against providers to access version information.
 	Locks map[addrs.Provider]*depsfile.ProviderLock
 
-	// Optional policy client to enable live policy evaluations.
+	// Optional policy client.
+	// When set, policy evaluation logic will be executed in the graph.
+	// When nil, that logic will be skipped.
 	PolicyClient  policy.Client
 	PolicyResults *plans.PolicyResults
 }

internal/terraform/context_plan_policy_test.go

@@ -958,16 +958,21 @@ func TestContext2Plan_PolicyEvaluation(t *testing.T) {
 					default = "default"
 				}
 
+				variable "input2" {
+					type    = string
+					default = "default"
+				}
+
 				resource "test_instance" "test" {
 					value = var.input
 				}
 				
 				resource "test_instance" "test2" {
-					value = resource.test_instance.test.id
+					value = var.input2
 				}
 
 				output "output" {
-					value = test_instance.test2.value
+					value = resource.test_instance.test.value
 				}
 			`,
 			prepareExpectations: func(t *testing.T, data *data) {

internal/terraform/node_module_expand.go

@@ -347,10 +347,10 @@ func (n *nodeExpandModule) EvalPolicy(ctx EvalContext, op walkOperation) tfdiags
 	// 	 value = var.input
 	// }
 	// resource "test_instance" "test2" {
-	// 	 value = resource.test_instance.test.id
+	// 	 value = var.input2
 	// }
 	// output "output" {
-	// 	 value = test_instance.test2.value
+	// 	 value = resource.test_instance.test.value
 	// }
 	//
 	// This is a valid terraform module call, but the input2 value depends on the module's output,