remove federated user in case of user deletion

models/user/user_repository.go

@@ -76,3 +76,8 @@ func FindFederatedUser(ctx context.Context, externalID string,
 	}
 	return user, federatedUser, nil
 }
+
+func DeleteFederatedUser(ctx context.Context, userID int64) error {
+	_, err := db.GetEngine(ctx).Delete(&FederatedUser{UserID: userID})
+	return err
+}

services/user/user.go

@@ -208,6 +208,13 @@ func DeleteUser(ctx context.Context, u *user_model.User, purge bool) error {
 				return err
 			}
 		}
+
+		// Delete Federated Users
+		if setting.Federation.Enabled {
+			if err := user_model.DeleteFederatedUser(ctx, u.ID); err != nil {
+				return err
+			}
+		}
 	}
 
 	ctx, committer, err := db.TxContext(ctx)