vendor/github.com/hashicorp/terraform/terraform/node_resource_plan_destroy.go

package terraform

import (
	"fmt"

	"github.com/hashicorp/terraform/addrs"
	"github.com/hashicorp/terraform/dag"
	"github.com/hashicorp/terraform/plans"
	"github.com/hashicorp/terraform/providers"
	"github.com/hashicorp/terraform/states"
)

// NodePlanDestroyableResourceInstance represents a resource that is ready
// to be planned for destruction.
type NodePlanDestroyableResourceInstance struct {
	*NodeAbstractResourceInstance
}

var (
	_ GraphNodeSubPath              = (*NodePlanDestroyableResourceInstance)(nil)
	_ GraphNodeReferenceable        = (*NodePlanDestroyableResourceInstance)(nil)
	_ GraphNodeReferencer           = (*NodePlanDestroyableResourceInstance)(nil)
	_ GraphNodeDestroyer            = (*NodePlanDestroyableResourceInstance)(nil)
	_ GraphNodeResource             = (*NodePlanDestroyableResourceInstance)(nil)
	_ GraphNodeResourceInstance     = (*NodePlanDestroyableResourceInstance)(nil)
	_ GraphNodeAttachResourceConfig = (*NodePlanDestroyableResourceInstance)(nil)
	_ GraphNodeAttachResourceState  = (*NodePlanDestroyableResourceInstance)(nil)
	_ GraphNodeEvalable             = (*NodePlanDestroyableResourceInstance)(nil)
	_ GraphNodeProviderConsumer     = (*NodePlanDestroyableResourceInstance)(nil)
)

// GraphNodeDestroyer
func (n *NodePlanDestroyableResourceInstance) DestroyAddr() *addrs.AbsResourceInstance {
	addr := n.ResourceInstanceAddr()
	return &addr
}

// GraphNodeEvalable
func (n *NodePlanDestroyableResourceInstance) EvalTree() EvalNode {
	addr := n.ResourceInstanceAddr()

	// Declare a bunch of variables that are used for state during
	// evaluation. These are written to by address in the EvalNodes we
	// declare below.
	var provider providers.Interface
	var providerSchema *ProviderSchema
	var change *plans.ResourceInstanceChange
	var state *states.ResourceInstanceObject

	if n.ResolvedProvider.ProviderConfig.Type == "" {
		// Should never happen; indicates that the graph was not constructed
		// correctly since we didn't get our provider attached.
		panic(fmt.Sprintf("%T %q was not assigned a resolved provider", n, dag.VertexName(n)))
	}

	return &EvalSequence{
		Nodes: []EvalNode{
			&EvalGetProvider{
				Addr:   n.ResolvedProvider,
				Output: &provider,
				Schema: &providerSchema,
			},
			&EvalReadState{
				Addr:           addr.Resource,
				Provider:       &provider,
				ProviderSchema: &providerSchema,

				Output: &state,
			},
			&EvalDiffDestroy{
				Addr:         addr.Resource,
				ProviderAddr: n.ResolvedProvider,
				State:        &state,
				Output:       &change,
			},
			&EvalCheckPreventDestroy{
				Addr:   addr.Resource,
				Config: n.Config,
				Change: &change,
			},
			&EvalWriteDiff{
				Addr:           addr.Resource,
				ProviderSchema: &providerSchema,
				Change:         &change,
			},
		},
	}
}