Setting the nat_gateway_enabled=false results in Invalid index error

[paulrob-100]

Describe the Bug

Setting the nat_gateway_enabled=false results in InvalidNatGatewayId.Malformed error on private subnets aws_route resource

Expected Behavior

Terraform apply should run without error and no routes to the nat gateways should exist in the private subnets

Steps to Reproduce

Steps to reproduce the behavior:

1. Go to examples/complete/main.tf
2. Edit nat_gateway_enabled = true to be nat_gateway_enabled = false
3. Run terraform apply -var-file fixtures.us-east-2.tfvars
4. See error InvalidNatGatewayId.Malformed: Invalid id: "0" (expecting "nat-...")

Screenshots

Not necessary

Environment (please complete the following information):

Anything that will help us triage the bug will help. Here are some ideas:

• OS:Linux
• TF Version 14.7

Additional Context

None

[paulrob-100]

Reran the test from #45 and confirmed it's still an issue.

    apply.go:15: 
        	Error Trace:	apply.go:15
        	            				examples_complete_test.go:148
        	Error:      	Received unexpected error:
        	            	FatalError{Underlying: error while running command: exit status 1; 
        	            	Error: Invalid index
        	            	
        	            	  on ../../main.tf line 13, in locals:
        	            	  13:     ngw_id         = local.public_enabled ? aws_nat_gateway.public[az].id : null
        	            	    |----------------
        	            	    | aws_nat_gateway.public is object with no attributes
        	            	
        	            	The given key does not identify an element in this collection value.
        	            	
        	            	
        	            	Error: Invalid index
        	            	
        	            	  on ../../main.tf line 13, in locals:
        	            	  13:     ngw_id         = local.public_enabled ? aws_nat_gateway.public[az].id : null
        	            	    |----------------
        	            	    | aws_nat_gateway.public is object with no attributes
        	            	
        	            	The given key does not identify an element in this collection value.
        	            	
        	            	
        	            	Error: Invalid index
        	            	
        	            	  on ../../main.tf line 13, in locals:
        	            	  13:     ngw_id         = local.public_enabled ? aws_nat_gateway.public[az].id : null
        	            	    |----------------
        	            	    | aws_nat_gateway.public is object with no attributes
        	            	
        	            	The given key does not identify an element in this collection value.
        	            	}
        	Test:       	TestExamplesCompleteNoNatGateway