BookStackApp/BookStack · error · ThemeModuleException

Failed loading module from "{$moduleJsonFile}" with error: {

Error message

Failed loading module from "{$moduleJsonFile}" with error: {$exception->getMessage()}

What it means

Wrapping ThemeModuleException rethrown in ThemeModuleManager::loadFromFolder when loading a module manifest fails for any reason (bad JSON or ThemeModule::fromJson validation failure); the original error text is embedded so the root cause of the failed module load is preserved.

Source

Thrown at app/Theming/ThemeModuleManager.php:135

    {
        $moduleJsonFile = $this->modulesFolderPath . DIRECTORY_SEPARATOR . $folderName . DIRECTORY_SEPARATOR . 'bookstack-module.json';
        if (!file_exists($moduleJsonFile)) {
            return null;
        }

        try {
            $jsonContent = file_get_contents($moduleJsonFile);
            $jsonData = json_decode($jsonContent, true);

            if (json_last_error() !== JSON_ERROR_NONE) {
                throw new ThemeModuleException("Invalid JSON in module file at \"{$moduleJsonFile}\": " . json_last_error_msg());
            }

            $module = ThemeModule::fromJson($jsonData, $folderName);
        } catch (ThemeModuleException $exception) {
            throw $exception;
        } catch (\Exception $exception) {
            throw new ThemeModuleException("Failed loading module from \"{$moduleJsonFile}\" with error: {$exception->getMessage()}");
        }

        return $module;
    }
}

View on GitHub (pinned to 18f8469a1c)

Solutions

1. Read the embedded original error message to identify whether it is invalid JSON or a missing/invalid manifest property
2. Fix the bookstack-module.json accordingly (syntax or required name/description/version fields)
3. Reinstall the theme module from a fresh copy if the file is corrupt

When it happens

Trigger: Thrown at app/Theming/ThemeModuleManager.php:135 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of BookStackApp/BookStack@18f8469a1c (2026-09-02). Data as JSON: /api/errors/a727d77319a47253. Report an issue: GitHub.