1. Programming Basics

\typo3\MyExtension

\TYPO3\CMS\MyExtension

\VendorName\MyExtension

\Symfony\Console

\vendor_name\my_extension

\AwesomeNerds\my_extension

They declare the type of an extension, e.g. “frontend plugin” or “backend module”.

They specify how many methods a PHP class may contain.

They specify the maximum time allowed to return an object.

They specify the type of the value that is returned from a function or method.

Return values can be marked as “nullable” by prefixing the type name with a question mark since PHP version 7.1.

The strict mode ensures that a variable passed to a function must exactly be of the declared type.

The strict mode allows developers to restrict access to class properties.

With the strict mode enabled, class names must be written in lowerCamelCase.

The strict mode can be enabled and disabled in the TYPO3 Install Tool as required.

The strict mode can be enabled by adding the line declare(strict_types = 1); at the top of
the PHP file.

The PHP strict mode must not be used in any TYPO3 extension files at all (TYPO3 v9 LTS does not support this feature).

The PHP strict mode must not be enabled in the file ext_tables.php.

The PHP strict mode must not be enabled in the file ext_localconf.php.

The PHP strict mode must not be enabled in any TCA files under Configuration/TCA/.

If the PHP strict mode is enabled in controller classes, the output of the action methods is not cached.

PHP coding guidelines, following the PSR-2 standard.

Style Guide for PHP Code (PEP-8).

Specific guidelines apply to PHP file and directory names.

The X-Mas Standard Policy applies to XLIFF language files.

The Airbnb JavaScript Style Guide should be used for JavaScript files.

TYPO3 is open-source software and therefore no coding guidelines exist.

Opening curly braces for classes must go on the same line.

Opening curly braces for classes must go on the next line.

Opening curly braces for if-statements must go on the same line.

Opening curly braces for if-statements must go on the next line.

TYPO3 does not adhere to any coding guidelines.

The maximum length of a line must not exceed 80 characters.

Code must use four spaces for indenting, not tabs.

A PHP file must not contain the closing PHP tag ?> at the end.

Spaces are not allowed at the end of lines.

Spaces are not allowed after a comma.

JavaScript files of the TYPO3 core must be located under typo3conf/assets/javascript/.

JavaScript files in extensions should be located under Resources/Public/JavaScript/.

TABs should be used for line indenting.

Strings should always use double-quotes (").

File endings of JavaScript files should be .js.

A versioning scheme following semantic versioning has exactly two numbers separated by
dots, e.g. 1.2.

A versioning scheme following semantic versioning has exactly three numbers separated by dots, e.g. 1.2.3.

A versioning scheme following semantic versioning has exactly four numbers separated by dots, e.g. 1.2.3.4.

The last number represents “patch” versions when developers make backwards-compatible bug fixes.

The first number indicates if a release is a long-term support release (LTS).

Semantic versioning dictates that LTS-releases are marked appropriately, e.g. 1.2.3-lts.

When developers fix a bug and release a backwards-compatible version, the patch number of the version should be increased.

Semantic versioning is part of the PSR-2 coding standard.

Semantic versioning introduces conventions about breaking changes and aim to make upgrade dependencies safe.

The property type must be set to typo3-cms-extension.

The property type must be set to plugin, if the extension provides a frontend plugin.

The extension version is required and must be set with the property version.

PHP classes should be auto-loaded with the appropriate namespace and path information.

By adding a file DO_NOT_UPDATE to the extension directory.

By adding the Composer namespace of the extension to the update-lock property in the composer.json file.

By setting the exact version number with composer require.

This is not possible, because composer update always forces updates.

composer install friendsoftypo3/extension-builder:9.10.2

composer install friendsoftypo3/extension-builder --version 9.10.2

composer require friendsoftypo3/extension-builder/9.10.2

composer require friendsoftypo3/extension-builder:9.10.2

composer require --version=9.10.2 --vendor=friendsoftypo3 extension-builder

The PSR-4 autoload information needs to be added to the file ext_localconf.php:
$GLOBALS['TYPO3_CONF_VARS']['autoload'][$_EXTKEY] = [
"psr-4" => [
"Vendor\\MyExtension\\": "Classes/"
]
];

The PSR-4 autoload information needs to be added to the file composer.json:
"autoload": {
"psr-4": {
"Vendor\\MyExtension\\": "Classes/"
}
}

A configuration file autoload.yaml in the typo3conf/ directory.

A configuration file autoload.php in the typo3temp/ directory.

=1.2.3

^1.2.3

~1.2.3

1.2.*

=bugfix

=1.2.3

^1.2.3

~1.2.3

*1.2.3

They should be used in TCA files located at Configuration/TCA/.

They must not be used in the ext_tables.php file.

They must not be used in the ext_localconf.php file.

They can not be used for type annotations of Extbase model properties.

Importing class names require PHP version 7.2 at least.

Importing class names only work, if this feature is enabled in the Install Tool.

In repository class definitions, when extending the class TYPO3\CMS\Extbase\Persistence\Repository.

In ext_localconf.php files of extensions.

In type annotations of Extbase controller action arguments.

Importing class names is not supported by TYPO3 and Extbase at all.

/**
* @param $blog \Vendor\MyExtension\Domain\Model\Blog
*/

/**
* @param \Vendor\MyExtension\Domain\Model\Blog $blog
*/

/** @var $blog \Vendor\MyExtension\Domain\Model\Blog */

// @var $blog \Vendor\MyExtension\Domain\Model\Blog