fix data_source_keycloak_user panic when user doesn't exist

keycloak/user.go

@@ -10,7 +10,7 @@ type FederatedIdentity struct {
 	UserName         string `json:"userName"`
 }
 
-type FederatedIdentities []FederatedIdentity
+type FederatedIdentities []*FederatedIdentity
 
 type User struct {
 	Id      string `json:"id,omitempty"`

provider/data_source_keycloak_user.go

@@ -1,6 +1,7 @@
 package provider
 
 import (
+	"fmt"
 	"github.com/hashicorp/terraform-plugin-sdk/v2/helper/schema"
 	"github.com/mrparkers/terraform-provider-keycloak/keycloak"
 )
@@ -66,6 +67,9 @@ func dataSourceKeycloakUserRead(data *schema.ResourceData, meta interface{}) err
 	if err != nil {
 		return err
 	}
+	if user == nil {
+		return fmt.Errorf("user with username %s not found", username)
+	}
 
 	mapFromUserToData(data, user)
 

provider/data_source_keycloak_user_test.go

@@ -2,6 +2,7 @@ package provider
 
 import (
 	"fmt"
+	"regexp"
 	"testing"
 
 	"github.com/hashicorp/terraform-plugin-sdk/v2/helper/acctest"
@@ -32,6 +33,23 @@ func TestAccKeycloakDataSourceUser(t *testing.T) {
 	})
 }
 
+func TestAccKeycloakDataSourceUser_gracefulError(t *testing.T) {
+	t.Parallel()
+	username := acctest.RandomWithPrefix("tf-acc")
+
+	resource.Test(t, resource.TestCase{
+		ProviderFactories: testAccProviderFactories,
+		PreCheck:          func() { testAccPreCheck(t) },
+		CheckDestroy:      testAccCheckKeycloakUserDestroy(),
+		Steps: []resource.TestStep{
+			{
+				Config:      testDataSourceKeycloakUser_NoUser(username),
+				ExpectError: regexp.MustCompile(fmt.Sprintf("user with username %s not found", username)),
+			},
+		},
+	})
+}
+
 func testAccCheckDataKeycloakUser(resourceName string) resource.TestCheckFunc {
 	return func(s *terraform.State) error {
 		rs, ok := s.RootModule().Resources[resourceName]
@@ -82,3 +100,16 @@ data "keycloak_user" "user" {
 }
 	`, testAccRealm.Realm, username)
 }
+
+func testDataSourceKeycloakUser_NoUser(username string) string {
+	return fmt.Sprintf(`
+data "keycloak_realm" "realm" {
+	realm = "%s"
+}
+
+data "keycloak_user" "user" {
+	realm_id 	= data.keycloak_realm.realm.id
+	username    = "%s"
+}
+	`, testAccRealm.Realm, username)
+}

provider/resource_keycloak_user.go

@@ -145,7 +145,7 @@ func getUserFederatedIdentitiesFromData(data []interface{}) *keycloak.FederatedI
 	var federatedIdentities keycloak.FederatedIdentities
 	for _, d := range data {
 		federatedIdentitiesData := d.(map[string]interface{})
-		federatedIdentity := keycloak.FederatedIdentity{
+		federatedIdentity := &keycloak.FederatedIdentity{
 			IdentityProvider: federatedIdentitiesData["identity_provider"].(string),
 			UserId:           federatedIdentitiesData["user_id"].(string),
 			UserName:         federatedIdentitiesData["user_name"].(string),