feat: allow emtpy invitation IDs (#1488)

* feat: allow emtpy invitation IDs

With this, for_each can be used with github_user_invitation_accepter resources
without producing errors for an empty invitation_id attribute.

* docs: improve documentation for current error states

* fix: set ForceNew

* fixup! feat: allow emtpy invitation IDs

* fix: allow resource to be saved

---------

Co-authored-by: Keegan Campbell <[email protected]>

Author: morremeyer

github/resource_github_user_invitation_accepter.go

@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"strconv"
 
+	"github.com/google/uuid"
 	"github.com/hashicorp/terraform-plugin-sdk/helper/schema"
 )
 
@@ -17,7 +18,13 @@ func resourceGithubUserInvitationAccepter() *schema.Resource {
 		Schema: map[string]*schema.Schema{
 			"invitation_id": {
 				Type:     schema.TypeString,
-				Required: true,
+				Optional: true,
+				ForceNew: true,
+			},
+			"allow_empty_id": {
+				Type:     schema.TypeBool,
+				Optional: true,
+				Default:  false,
 				ForceNew: true,
 			},
 		},
@@ -28,6 +35,19 @@ func resourceGithubUserInvitationAccepterCreate(d *schema.ResourceData, meta int
 	client := meta.(*Owner).v3client
 
 	invitationIdString := d.Get("invitation_id").(string)
+	allowEmptyId := d.Get("allow_empty_id").(bool)
+
+	if invitationIdString == "" {
+		if allowEmptyId {
+			// We're setting a random UUID as resource ID since every resource needs an ID
+			// and we can't destroy the resource while we create it.
+			d.SetId(uuid.NewString())
+			return nil
+		} else {
+			return fmt.Errorf("invitation_id is not set and allow_empty_id is false")
+		}
+	}
+
 	invitationId, err := strconv.Atoi(invitationIdString)
 	if err != nil {
 		return fmt.Errorf("failed to parse invitation ID: %s", err)

github/resource_github_user_invitation_accepter_test.go

@@ -39,6 +39,27 @@ func TestAccGithubUserInvitationAccepter_basic(t *testing.T) {
 	})
 }
 
+func TestAccGithubUserInvitationAccepterAllowEmptyId(t *testing.T) {
+	rn := "github_user_invitation_accepter.test"
+
+	var providers []*schema.Provider
+
+	resource.ParallelTest(t, resource.TestCase{
+		PreCheck:          func() { testAccPreCheck(t) },
+		ProviderFactories: testAccProviderFactories(&providers),
+		CheckDestroy:      testAccCheckGithubUserInvitationAccepterDestroy,
+		Steps: []resource.TestStep{
+			{
+				Config: testAccGithubUserInvitationAccepterAllowEmptyId(),
+				Check: resource.ComposeTestCheckFunc(
+					resource.TestCheckResourceAttr(rn, "invitation_id", ""),
+					resource.TestCheckResourceAttr(rn, "allow_empty_id", "true"),
+				),
+			},
+		},
+	})
+}
+
 func testAccCheckGithubUserInvitationAccepterDestroy(s *terraform.State) error {
 	return nil
 }
@@ -72,3 +93,14 @@ resource "github_user_invitation_accepter" "test" {
 }
 `, inviteeToken, repoName, testCollaborator)
 }
+
+func testAccGithubUserInvitationAccepterAllowEmptyId() string {
+	return `
+provider "github" {}
+
+resource "github_user_invitation_accepter" "test" {
+  invitation_id  = ""
+  allow_empty_id = true
+}
+`
+}

website/docs/r/user_invitation_accepter.html.markdown

@@ -30,11 +30,24 @@ provider "github" {
 resource "github_user_invitation_accepter" "example" {
   provider      = "github.invitee"
   invitation_id = github_repository_collaborator.example.invitation_id
-} 
+}
 ```
 
+## Allowing empty invitation IDs
+
+Set `allow_empty_id` when using `for_each` over a list of `github_repository_collaborator.invitation_id`'s.
+
+This allows applying a module again when a new `github_repository_collaborator` resource is added to the `for_each` loop.
+This is needed as the `github_repository_collaborator.invitation_id` will be empty after a state refresh when the invitation has been accepted.
+
+Note that when an invitation is accepted manually or by another tool between a state refresh and a `terraform apply` using that refreshed state,
+the plan will contain the invitation ID, but the apply will receive an HTTP 404 from the API since the invitation has already been accepted.
+
+This is tracked in [#1157](https://github.com/integrations/terraform-provider-github/issues/1157).
+
 ## Argument Reference
 
 The following arguments are supported:
 
-* `invitation_id` - (Required) ID of the invitation to accept
+* `invitation_id` - (Optional) ID of the invitation to accept. Must be set when `allow_empty_id` is `false`.
+* `allow_empty_id` - (Optional) Allow the ID to be unset. This will result in the resource being skipped when the ID is not set instead of returning an error.