opentofu/terraform/transform_orphan_count.go

package terraform

import (
	"log"

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

// OrphanResourceCountTransformer is a GraphTransformer that adds orphans
// for an expanded count to the graph. The determination of this depends
// on the count argument given.
//
// Orphans are found by comparing the count to what is found in the state.
// This transform assumes that if an element in the state is within the count
// bounds given, that it is not an orphan.
type OrphanResourceCountTransformer struct {
	Concrete ConcreteResourceInstanceNodeFunc

	Addr          addrs.ConfigResource        // Addr of the resource to look for orphans
	InstanceAddrs []addrs.AbsResourceInstance // Addresses that currently exist in config
	State         *states.State               // Full global state
}

func (t *OrphanResourceCountTransformer) Transform(g *Graph) error {
	resources := t.State.Resources(t.Addr)
	if len(resources) == 0 {
		return nil // Resource doesn't exist in state, so nothing to do!
	}

	for _, rs := range resources {
		// This is an O(n*m) analysis, which we accept for now because the
		// number of instances of a single resource ought to always be small in any
		// reasonable Terraform configuration.
	Have:
		for key := range rs.Instances {
			thisAddr := rs.Addr.Instance(key)
			for _, wantAddr := range t.InstanceAddrs {
				if wantAddr.Equal(thisAddr) {
					continue Have
				}
			}
			// If thisAddr is not in t.InstanceAddrs then we've found an "orphan"

			abstract := NewNodeAbstractResourceInstance(thisAddr)
			var node dag.Vertex = abstract
			if f := t.Concrete; f != nil {
				node = f(abstract)
			}
			log.Printf("[TRACE] OrphanResourceCountTransformer: adding %s as %T", thisAddr, node)
			g.Add(node)
		}
	}

	return nil
}