diff --git a/typo3/sysext/core/Classes/Configuration/ConfigurationManager.php b/typo3/sysext/core/Classes/Configuration/ConfigurationManager.php
index 05e60cd2d74b7391d2eb1a72dc3e897d457969c8..d3ce2786c824e63db8c2e71cae69136af029df0d 100644
--- a/typo3/sysext/core/Classes/Configuration/ConfigurationManager.php
+++ b/typo3/sysext/core/Classes/Configuration/ConfigurationManager.php
@@ -286,6 +286,30 @@ class ConfigurationManager
return $result;
}
+ /**
+ * Enables a certain feature and writes the option to LocalConfiguration.php
+ * Short-hand method
+ *
+ * @param string $featureName something like "InlineSvgImages"
+ * @return bool true on successful writing the setting
+ */
+ public function enableFeature(string $featureName): bool
+ {
+ return $this->setLocalConfigurationValueByPath('SYS/features/' . $featureName, true);
+ }
+
+ /**
+ * Disables a feature and writes the option to LocalConfiguration.php
+ * Short-hand method
+ *
+ * @param string $featureName something like "InlineSvgImages"
+ * @return bool true on successful writing the setting
+ */
+ public function disableFeature(string $featureName): bool
+ {
+ return $this->setLocalConfigurationValueByPath('SYS/features/' . $featureName, false);
+ }
+
/**
* Checks if the configuration can be written.
*
diff --git a/typo3/sysext/core/Classes/Configuration/Features.php b/typo3/sysext/core/Classes/Configuration/Features.php
new file mode 100644
index 0000000000000000000000000000000000000000..1cc4004018360f3a49fe6f888f440ca690ceaf34
--- /dev/null
+++ b/typo3/sysext/core/Classes/Configuration/Features.php
@@ -0,0 +1,65 @@
+<?php
+declare(strict_types=1);
+namespace TYPO3\CMS\Core\Configuration;
+
+/*
+ * This file is part of the TYPO3 CMS project.
+ *
+ * It is free software; you can redistribute it and/or modify it under
+ * the terms of the GNU General Public License, either version 2
+ * of the License, or any later version.
+ *
+ * For the full copyright and license information, please read the
+ * LICENSE.txt file that was distributed with this source code.
+ *
+ * The TYPO3 project - inspiring people to share!
+ */
+
+/**
+ * A lightweight API class to check if a feature is enabled.
+ *
+ * Features are simple options (true/false), and are stored in the
+ * global configuration array $TYPO3_CONF_VARS[SYS][features].
+ *
+ * For disabling or enabling a feature the "ConfigurationManager"
+ * should be used.
+ *
+ * -- Naming --
+ *
+ * Feature names should NEVER named "enable" or having a negation, or containing versions or years
+ * "enableFeatureXyz"
+ * "disableOverlays"
+ * "schedulerRevamped"
+ * "useDoctrineQueries"
+ * "disablePreparedStatements"
+ * "disableHooksInFE"
+ *
+ * Proper namings for features
+ * "ExtendedRichtextFormat"
+ * "NativeYamlParser"
+ * "InlinePageTranslations"
+ * "TypoScriptParserIncludesAsXml"
+ * "NativeDoctrineQueries"
+ *
+ * Ideally, these feature switches are added via the Install Tool or via FactoryConfiguration
+ * and can be used for Extensions as well.
+ *
+ * --- Usage ---
+ *
+ * if (GeneralUtility::makeInstance(Features::class)->isFeatureEnabled('InlineSvg')) {
+ * ... do stuff here ...
+ * }
+ */
+class Features
+{
+ /**
+ * Checks if a feature is active
+ *
+ * @param string $featureName the name of the feature
+ * @return bool
+ */
+ public function isFeatureEnabled(string $featureName): bool
+ {
+ return isset($GLOBALS['TYPO3_CONF_VARS']['SYS']['features'][$featureName]) && $GLOBALS['TYPO3_CONF_VARS']['SYS']['features'][$featureName] === true;
+ }
+}
diff --git a/typo3/sysext/core/Configuration/DefaultConfiguration.php b/typo3/sysext/core/Configuration/DefaultConfiguration.php
index 8a5cc4279d03ec2db01c87cf297b77928afcaf45..6edf83a26d23fb16b9acd70ae0fb0456b8ac6ba7 100644
--- a/typo3/sysext/core/Configuration/DefaultConfiguration.php
+++ b/typo3/sysext/core/Configuration/DefaultConfiguration.php
@@ -67,6 +67,7 @@ return [
],
'fileCreateMask' => '0664',
'folderCreateMask' => '2775',
+ 'features' => [],
'createGroup' => '',
'sitename' => 'TYPO3',
'encryptionKey' => '',
diff --git a/typo3/sysext/core/Documentation/Changelog/master/Feature-83429-FeatureToggles.rst b/typo3/sysext/core/Documentation/Changelog/master/Feature-83429-FeatureToggles.rst
new file mode 100644
index 0000000000000000000000000000000000000000..952ed62ca7263ac3443e43823fdc4ec2a95867d4
--- /dev/null
+++ b/typo3/sysext/core/Documentation/Changelog/master/Feature-83429-FeatureToggles.rst
@@ -0,0 +1,40 @@
+.. include:: ../../Includes.txt
+
+=================================
+Feature: #83429 - Feature Toggles
+=================================
+
+See :issue:`83429`
+
+Description
+===========
+
+In order to allow better support for alternative functionality while keeping old functionality, a new API
+for enabling installation-wide features - called "Feature Toggle" - has been added.
+
+The new API checks against a system-wide option array within :php:`$TYPO3_CONF_VARS['SYS']['features']` which can be
+enabled system-wide. Both TYPO3 Core and Extensions can then provide alternative functionality for a certain
+feature.
+
+Features are usually breaking changes for a minor version / sprint release, which site administrators can enable
+at their own risk, or stay fully compatible with third-party extensions.
+
+Examples for having features are:
+* Throw exceptions on certain occasions instead of just returning a string message as error message.
+* Disable obsolete functionality which might still be used, but slows down the system.
+* Enable alternative PageNotFound handling for an installation.
+
+
+Impact
+======
+
+Features are documented for TYPO3 Core. For extension authors, the API can be used for any custom
+feature provided by an extension:
+
+.. code-block:: php
+
+ if (GeneralUtility::makeInstance(Features::class)->isFeatureEnabled('myFeatureName')) {
+ // do custom processing
+ }
+
+.. index:: LocalConfiguration, PHP-API
diff --git a/typo3/sysext/core/Tests/Unit/Configuration/FeaturesTest.php b/typo3/sysext/core/Tests/Unit/Configuration/FeaturesTest.php
new file mode 100644
index 0000000000000000000000000000000000000000..8f093aac07bdd83c457f4b6052cd89a4754f9b75
--- /dev/null
+++ b/typo3/sysext/core/Tests/Unit/Configuration/FeaturesTest.php
@@ -0,0 +1,64 @@
+<?php
+declare(strict_types=1);
+namespace TYPO3\CMS\Core\Tests\Unit\Configuration;
+
+/*
+ * This file is part of the TYPO3 CMS project.
+ *
+ * It is free software; you can redistribute it and/or modify it under
+ * the terms of the GNU General Public License, either version 2
+ * of the License, or any later version.
+ *
+ * For the full copyright and license information, please read the
+ * LICENSE.txt file that was distributed with this source code.
+ *
+ * The TYPO3 project - inspiring people to share!
+ */
+
+use TYPO3\CMS\Core\Configuration\Features;
+use TYPO3\TestingFramework\Core\Unit\UnitTestCase;
+
+/**
+ * Test case
+ */
+class FeaturesTest extends UnitTestCase
+{
+ /**
+ * @test
+ */
+ public function nonExistingFeatureReturnsFalse()
+ {
+ $features = new Features();
+ $this->assertFalse($features->isFeatureEnabled('nonExistingFeature'));
+ }
+
+ /**
+ * @test
+ */
+ public function checkIfExistingDisabledFeatureIsDisabled()
+ {
+ $GLOBALS['TYPO3_CONF_VARS']['SYS']['features']['nativeFunctionality'] = false;
+ $features = new Features();
+ $this->assertFalse($features->isFeatureEnabled('nativeFunctionality'));
+ }
+
+ /**
+ * @test
+ */
+ public function checkIfExistingEnabledFeatureIsEnabled()
+ {
+ $GLOBALS['TYPO3_CONF_VARS']['SYS']['features']['nativeFunctionality'] = true;
+ $features = new Features();
+ $this->assertTrue($features->isFeatureEnabled('nativeFunctionality'));
+ }
+
+ /**
+ * @test
+ */
+ public function checkIfExistingEnabledFeatureIsDisabled()
+ {
+ $GLOBALS['TYPO3_CONF_VARS']['SYS']['features']['nativeFunctionality'] = false;
+ $features = new Features();
+ $this->assertFalse($features->isFeatureEnabled('nativeFunctionality'));
+ }
+}