Validate removed attributes before required ones

[QuentinBrosse]

Hi,

Validate the removed attributes before the required ones would allow a better UX.

Example

Here is the first version of a test schema:

&schema.Resource{
	Schema: map[string]*schema.Schema{
		"offer_id": {
			Type:     schema.TypeString,
			Required: true,
			ForceNew: true,
		},
	},
}

A bit later, we decide to replace the offer_id by offer (to handle offer name and UUID in the same attribute). After depreciating the offer_id field during some releases, we decide to remove it with the Schema.Removed field:

&schema.Resource{
	Schema: map[string]*schema.Schema{
		"offer": {
			Type:     schema.TypeString,
			Required: true,
			ForceNew: true,
		},
		"offer_id": {
			Type:     schema.TypeString,
			Optional: true,
			Removed:  "Please use offer attribute instead",
		},
	},
}

After the provider update, the user will still have this old configuration:

resource "scaleway_test" "test" {
  offer_id = "11111111-1111-1111-1111-111111111111"
}

The terraform [validate|plan] command will throw this error:

Error: Missing required argument

  on example.tf line 15, in resource "scaleway_bla" "bla":
  15: resource "scaleway_test" "test" {

The argument "offer" is required, but no definition was found.

The user does not understand why the offer attribute is required, he already has an offer_id attribute. If the removed validation was done before the required one, the user would have this error:

Error: "offer_id": [REMOVED] Please use offer attribute instead

  on example.tf line 15, in resource "scaleway_bla" "bla":
  15: resource "scaleway_test" "test" {

In this way, the user will understand easily that the offer_id attribute has been replaced by the offer one.

[paultyng]

We are planning to drop support for Removed in v2, so this issue will no longer be relevant I believe.

See #320 for tracking the removal.

[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.

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