Check if client grant already exists before creating

internal/auth0/client/resource_grant.go

@@ -52,6 +52,19 @@ func NewGrantResource() *schema.Resource {
 func createClientGrant(ctx context.Context, d *schema.ResourceData, m interface{}) diag.Diagnostics {
 	api := m.(*management.Management)
 
+	grantList, err := api.ClientGrant.List(
+		management.Parameter("audience", d.Get("audience").(string)),
+		management.Parameter("client_id", d.Get("client_id").(string)),
+	)
+	if err != nil {
+		return diag.FromErr(err)
+	}
+
+	if len(grantList.ClientGrants) != 0 {
+		d.SetId(grantList.ClientGrants[0].GetID())
+		return readClientGrant(ctx, d, m)
+	}
+
 	clientGrant := expandClientGrant(d)
 	if err := api.ClientGrant.Create(clientGrant); err != nil {
 		return diag.FromErr(err)

internal/auth0/client/resource_grant_test.go

@@ -69,6 +69,28 @@ resource "auth0_client_grant" "my_client_grant" {
 }
 `
 
+const testAccAlreadyExistingGrantWillNotConflict = testAccClientGrantAuxConfig + `
+resource "auth0_client" "my_client_alt" {
+	name = "Acceptance Test - Client Grant Alt - {{.testName}}"
+	custom_login_page_on = true
+	is_first_party = true
+}
+
+resource "auth0_client_grant" "my_client_grant" {
+	client_id = "${auth0_client.my_client_alt.id}"
+	audience = "${auth0_resource_server.my_resource_server.identifier}"
+	scope = [ ]
+}
+
+resource "auth0_client_grant" "no_conflict_client_grant" {
+	depends_on = [ auth0_client_grant.my_client_grant ]
+
+	client_id = "${auth0_client.my_client_alt.id}"
+	audience = "${auth0_resource_server.my_resource_server.identifier}"
+	scope = [ ]
+}
+`
+
 func TestAccClientGrant(t *testing.T) {
 	acctest.Test(t, resource.TestCase{
 		Steps: []resource.TestStep{
@@ -98,6 +120,12 @@ func TestAccClientGrant(t *testing.T) {
 					resource.TestCheckResourceAttr("auth0_client_grant.my_client_grant", "scope.#", "0"),
 				),
 			},
+			{
+				Config: template.ParseTestName(testAccAlreadyExistingGrantWillNotConflict, t.Name()),
+				Check: resource.ComposeTestCheckFunc(
+					resource.TestCheckResourceAttr("auth0_client_grant.no_conflict_client_grant", "scope.#", "0"),
+				),
+			},
 		},
 	})
 }