Changing only memo of a service/role causes recreation of itself

[Arthur1]

Problem

If you change memo attribute of a service, it is destroyed and recreated.

Terraform used the selected providers to generate the following execution plan. Resource actions are indicated with
the following symbols:
-/+ destroy and then create replacement

Terraform will perform the following actions:

  # mackerel_service.foo must be replaced
-/+ resource "mackerel_service" "foo" {
      ~ id   = "foo" -> (known after apply)
      + memo = "aa" # forces replacement
        name = "foo"
    }

Plan: 1 to add, 0 to change, 1 to destroy.

At this time, information associated with the service such as roles and monitor rule options will be lost. This specification is almost always inconvenient.

Role memo has the same problem.

-/+ destroy and then create replacement

Terraform will perform the following actions:

  # mackerel_role.bar must be replaced
-/+ resource "mackerel_role" "bar" {
      ~ id      = "foo:bar" -> (known after apply)
      ~ memo    = "foo:bar is managed by Terraform" -> "foo:bar is managed by Terraform 2" # forces replacement
        name    = "bar"
        # (1 unchanged attribute hidden)
    }

Plan: 1 to add, 0 to change, 1 to destroy.

Solution

terraform-provider-mackerel/mackerel/resource_mackerel_service.go

Lines 21 to 37 in 780e445

	Schema: map[string]*schema.Schema{
	"name": {
	Type: schema.TypeString,
	Required: true,
	ForceNew: true,
	ValidateFunc: validation.All(
	validation.StringLenBetween(2, 63),
	validation.StringMatch(regexp.MustCompile(`^[a-zA-Z0-9][a-zA-Z0-9-_]+$`),
	"must include only alphabets, numbers, hyphen and underscore, and it can not begin a hyphen or underscore"),
	),
	},
	"memo": {
	Type: schema.TypeString,
	Optional: true,
	ForceNew: true,
	},
	},

It would seem that erasing ForceNew: true in memo would solve the problem.