terraform apply command doesn't present diff between false and null

[chkp-idoma]

Terraform Version

Terraform v0.12.13

Terraform Configuration Files

Custom Provider:

func resourceTest() *schema.Resource {
	return &schema.Resource{
		Create: createTest,
		Read:   readTest,
		Update: updateTest,
		Delete: deleteTest,

		Schema: map[string]*schema.Schema{
			"name": &schema.Schema{
				Type:     schema.TypeString,
				Required: true,
			},
			"enable": &schema.Schema{
				Type:     schema.TypeBool,
				Optional: true,
			},
		},
	}
}

func createTest(d *schema.ResourceData, m interface{}) error {

	d.SetId("1234")
	return readTest(d, m)
}

func readTest(d *schema.ResourceData, m interface{}) error{

	_ = d.Set("name", d.Get("name"))

	return nil
}

func updateTest(d *schema.ResourceData, m interface{}) error {

	if d.HasChange("enable") {

		log.Println("enable changed")
		_ = d.Set("enable", d.Get("enable"))
	}

	return readTest(d, m)
}

func deleteTest(d *schema.ResourceData, m interface{}) error {
	return nil
}

Configuration file (.tf) on first terraform apply:

resource "temp" "example" {
  name = "test1"
}

Configuration file (.tf) on second terraform apply:

resource "temp" "example" {
  name = "test1"
  enable = false
}

Expected Behavior

On the second run of terraform apply, diff should be presented:

Terraform will perform the following actions:
# temp.example will be updated in-place
 ~ resource "temp" "example" {
          name = "test1"
      + enable = false
    }

Actual Behavior

temp.example: Refreshing state... [id=1234]

Apply complete! Resources: 0 added, 0 changed, 0 destroyed.

Steps to Reproduce

1. build the custom provider with this single resource
2. write .tf file with the resource as shown in "Configuration file (.tf) on first terraform apply:"
3. terraform init
4. terraform apply
5. change the .tf file as shown in "Configuration file (.tf) on second terraform apply:"
6. terraform apply

Additional Context

I'm trying to show here that when TypeBool argument isn't set at the first run of terraform apply,
and in the second run this boolean argument is set to false in the configuration file, no diff shown.
It means there is no difference between false and null values in the .tfstate file.

*if this issue isn't related to this section please tell me where to open it.

[appilon]

Hello @chkp-idoma unfortunately this is a known limitation of the current SDK, you cannot distinguish between Go's zero value and "unset/null". With other types, such as TypeInt you can work around this by using a sentinel value, such as -1, but with TypeBool unfortunately there are no tricks. We will be addressing this in future major releases of the SDK.

Related issue: #173

[chkp-idoma]

Hi @appilon ,

Thanks for answering!

Is there any time estimation for this fix to be released?

[radeksimko]

Hi folks,
I'm going to close this as a duplicate of #102 as I believe it covers the exact same problem with a bit more context on why (which Alex also mentioned).

@chkp-idoma We tend not to publish any release dates, but I can say that supporting 0.12 types is one of our current priorities. We are practically sure though that supporting these in the provider will require deprecation of <0.12 from provider's perspective as only 0.12 uses the new protocol that allows us to carry all the important details about types.

The best you can do in the meantime is to read this blogpost, share it and encourage everyone to upgrade to 0.12.

[ghost]

I'm going to lock this issue because it has been closed for 30 days ⏳. This helps our maintainers find and focus on the active issues.

If you have found a problem that seems similar to this, please open a new issue and complete the issue template so we can capture all the details necessary to investigate further.