Piwik\Plugins\CorePluginsAdmin\PluginInstaller::makeSurePluginJsonExists PHP Method

    private function makeSurePluginJsonExists($tmpPluginFolder)
    {
        $pluginJsonPath = $this->getPathToPluginJson($tmpPluginFolder);
        if (!file_exists($pluginJsonPath)) {
            throw new PluginInstallerException('Plugin is not valid, it is missing the plugin.json file.');
        }
    }