defaultFalse example

public function getConfigTreeBuilder(): TreeBuilder
    {
        $treeBuilder = new TreeBuilder('storefront');

        $rootNode = $treeBuilder->getRootNode();

        $rootNode
            ->children()
                ->arrayNode('reverse_proxy')
                    ->children()
                        ->booleanNode('enabled')->end()
                        ->booleanNode('use_varnish_xkey')->defaultFalse()->end()
                        ->arrayNode('hosts')->performNoDeepMerging()->scalarPrototype()->end()->end()
                        ->integerNode('max_parallel_invalidations')->defaultValue(2)->end()
                        ->scalarNode('redis_url')->end()
                        ->scalarNode('ban_method')->defaultValue('BAN')->end()
                        ->arrayNode('ban_headers')->performNoDeepMerging()->defaultValue([])->scalarPrototype()->end()->end()
                        ->arrayNode('purge_all')
                            ->children()
                                ->scalarNode('ban_method')->defaultValue('BAN')->end()
                                ->arrayNode('ban_headers')->performNoDeepMerging()->defaultValue([])->scalarPrototype()->end()->end()
                                ->arrayNode('urls')->performNoDeepMerging()->defaultValue(['/'])->scalarPrototype()->end()->end()
                            ->end()
                        

->booleanNode('hide_user_not_found')->defaultTrue()->end()
                ->booleanNode('erase_credentials')->defaultTrue()->end()
                ->booleanNode('enable_authenticator_manager')->setDeprecated('symfony/security-bundle', '6.2', 'The "%node%" option at "%path%" is deprecated.')->defaultTrue()->end()
                ->arrayNode('access_decision_manager')
                    ->addDefaultsIfNotSet()
                    ->children()
                        ->enumNode('strategy')
                            ->values($this->getAccessDecisionStrategies())
                        ->end()
                        ->scalarNode('service')->end()
                        ->scalarNode('strategy_service')->end()
                        ->booleanNode('allow_if_all_abstain')->defaultFalse()->end()
                        ->booleanNode('allow_if_equal_granted_denied')->defaultTrue()->end()
                    ->end()
                    ->validate()
                        ->ifTrue(fn ($v) => isset($v['strategy'], $v['service']))
                        ->thenInvalid('"strategy" and "service" cannot be used together.')
                    ->end()
                    ->validate()
                        ->ifTrue(fn ($v) => isset($v['strategy'], $v['strategy_service']))
                        ->thenInvalid('"strategy" and "strategy_service" cannot be used together.')
                    ->end()
                    ->validate()
                        

->treatNullLike(['enabled' => true])
            ->beforeNormalization()
                ->ifArray()
                ->then(function Darray $v) {
                    $v['enabled'] ??= true;

                    return $v;
                })
            ->end()
            ->children()
                ->booleanNode('enabled')
                    ->defaultFalse()
        ;

        return $this;
    }

    /** * Adds an "enabled" boolean to enable the current section. * * By default, the section is enabled. * * @return $this */

private function createFeatureSection(): ArrayNodeDefinition
    {
        $rootNode = (new TreeBuilder('feature'))->getRootNode();
        $rootNode
            ->children()
            ->arrayNode('flags')
                ->useAttributeAsKey('name')
                ->arrayPrototype()
                    ->children()
                        ->scalarNode('name')->end()
                        ->booleanNode('default')->defaultFalse()->end()
                        ->booleanNode('major')->defaultFalse()->end()
                        ->scalarNode('description')->end()
                    ->end()
                ->end()
                ->beforeNormalization()
                    ->always()->then(function D$flags) {
                        foreach ($flags as $key => $flag) {
                            // support old syntax                             if (\is_int($key) && \is_string($flag)) {
                                unset($flags[$key]);

                                

class Configuration implements ConfigurationInterface
{
    /** * Generates the configuration tree builder. */
    public function getConfigTreeBuilder(): TreeBuilder
    {
        $treeBuilder = new TreeBuilder('web_profiler');

        $treeBuilder->getRootNode()
            ->children()
                ->booleanNode('toolbar')->defaultFalse()->end()
                ->booleanNode('intercept_redirects')->defaultFalse()->end()
                ->scalarNode('excluded_ajax_paths')->defaultValue('^/((index|app(_[\w]+)?)\.php/)?_wdt')->end()
            ->end()
        ;

        return $treeBuilder;
    }
}

            ->end()
            ->fixXmlConfig('enabled_locale')
            ->children()
                ->scalarNode('secret')->end()
                ->booleanNode('http_method_override')
                    ->info("Set true to enable support for the '_method' request parameter to determine the intended HTTP method on POST requests. Note: When using the HttpCache, you need to call the method in your front controller instead")
                    ->treatNullLike(false)
                ->end()
                ->scalarNode('trust_x_sendfile_type_header')
                    ->info('Set true to enable support for xsendfile in binary file responses.')
                    ->defaultFalse()
                ->end()
                ->scalarNode('ide')->defaultValue('%env(default::SYMFONY_IDE)%')->end()
                ->booleanNode('test')->end()
                ->scalarNode('default_locale')->defaultValue('en')->end()
                ->booleanNode('set_locale_from_accept_language')
                    ->info('Whether to use the Accept-Language HTTP header to set the Request locale (only when the "_locale" request attribute is not passed).')
                    ->defaultFalse()
                ->end()
                ->booleanNode('set_content_language_from_locale')
                    ->info('Whether to set the Content-Language HTTP header on the Response using the Request locale.')
                    ->defaultFalse()
                

public function addConfiguration(NodeDefinition $node): void
    {
        /** @var NodeBuilder $builder */
        $builder = $node->fixXmlConfig('signature_property', 'signature_properties')->children();

        $builder
            ->scalarNode('check_route')
                ->isRequired()
                ->info('Route that will validate the login link - e.g. "app_login_link_verify".')
            ->end()
            ->scalarNode('check_post_only')
                ->defaultFalse()
                ->info('If true, only HTTP POST requests to "check_route" will be handled by the authenticator.')
            ->end()
            ->arrayNode('signature_properties')
                ->isRequired()
                ->prototype('scalar')->end()
                ->requiresAtLeastOneElement()
                ->info('An array of properties on your User that are used to sign the link. If any of these change, all existing links will become invalid.')
                ->example(['email', 'password'])
            ->end()
            ->integerNode('lifetime')
                ->defaultValue(600)
                

$treeBuilder = new TreeBuilder('acme_root');

        $treeBuilder->getRootNode()
            ->fixXmlConfig('parameter')
            ->fixXmlConfig('connection')
            ->fixXmlConfig('cms_page')
            ->children()
                ->booleanNode('boolean')->defaultTrue()->end()
                ->scalarNode('scalar_empty')->end()
                ->scalarNode('scalar_null')->defaultNull()->end()
                ->scalarNode('scalar_true')->defaultTrue()->end()
                ->scalarNode('scalar_false')->defaultFalse()->end()
                ->scalarNode('scalar_default')->defaultValue('default')->end()
                ->scalarNode('scalar_array_empty')->defaultValue([])->end()
                ->scalarNode('scalar_array_defaults')->defaultValue(['elem1', 'elem2'])->end()
                ->scalarNode('scalar_required')->isRequired()->end()
                ->scalarNode('scalar_deprecated')->setDeprecated('vendor/package', '1.1')->end()
                ->scalarNode('scalar_deprecated_with_message')->setDeprecated('vendor/package', '1.1', 'Deprecation custom message for "%node%" at "%path%"')->end()
                ->scalarNode('node_with_a_looong_name')->end()
                ->enumNode('enum_with_default')->values(['this', 'that'])->defaultValue('this')->end()
                ->enumNode('enum')->values(['this', 'that', TestEnum::Ccc])->end()
                ->arrayNode('array')
                    ->info('some info')
                    

use Symfony\Component\Config\Definition\Builder\TreeBuilder;
use Symfony\Component\Config\Definition\ConfigurationInterface;

class Placeholders implements ConfigurationInterface
{
    public function getConfigTreeBuilder(): TreeBuilder
    {
        $tb = new TreeBuilder('placeholders');
        $rootNode = $tb->getRootNode();
        $rootNode
            ->children()
                ->booleanNode('enabled')->defaultFalse()->end()
                ->floatNode('favorite_float')->end()
                ->arrayNode('good_integers')
                    ->integerPrototype()->end()
                ->end()
            ->end()
        ;

        return $tb;
    }
}