octobercms/october · error · ApplicationException

backend::lang.model.invalid_class

Error message

backend::lang.model.invalid_class

What it means

Error "backend::lang.model.invalid_class" thrown in octobercms/october.

Source

Thrown at modules/backend/behaviors/RelationController.php:369

            $field = post(self::PARAM_FIELD);
        }

        $this->config = $this->originalConfig;
        $this->model = $model;
        $this->field = $field;

        if (!$field) {
            return;
        }

        if (!$this->model) {
            throw new ApplicationException(Lang::get('backend::lang.relation.missing_model', [
                'class' => get_class($this->controller),
            ]));
        }

        if (!$this->model instanceof Model) {
            throw new ApplicationException(Lang::get('backend::lang.model.invalid_class', [
                'model' => get_class($this->model),
                'class' => get_class($this->controller),
            ]));
        }

        // Configuration details
        if (!$this->relationHasField($field)) {
            throw new ApplicationException(Lang::get('backend::lang.relation.missing_definition', compact('field')));
        }

        $this->applyExtraConfig($field);
        $this->alias = camel_case('relation ' . HtmlHelper::nameToId($field));
        $this->config = $this->makeConfig($this->originalConfig->{$field}, $this->requiredRelationProperties);
        $this->controller->relationExtendConfig($this->config, $this->field, $this->model);
        $this->manageId = $this->getManageIdForField($field);
        $this->pivotId = post('pivot_id');
        $this->foreignId = post('foreign_id');
        [$this->sessionKey, $this->relationSessionKey] = $this->getSessionKeysForField($field);

View on GitHub (pinned to b608633a7e)

When it happens

Trigger: Thrown at modules/backend/behaviors/RelationController.php:369 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of octobercms/october@b608633a7e (2026-08-21). Data as JSON: /api/errors/508cb10dd5ae3706. Report an issue: GitHub.