Feature: #70078 - Extensions can provide a class map for class loading

See Issue #70078

Description

With the old class loader it was possible for extension authors to register several classes in an ext_autoload.php file.

This possibility was completely removed with introduction of composer class loading. In composer mode, one can fully benefit from composer and its class loading options. However TYPO3 installations in non composer mode (extracted and symlinked archive of sources), lack this functionality completely.

Now it is possible to provide a class map section in either the composer.json file or the ext_emconf.php file. This section will be evaluated and used also in non composer mode.

Example ext_emconf.php file:

<?php
$EM_CONF[$_EXTKEY] = array (
  'title' => 'Extension skeleton for TYPO3 7',
  'description' => 'Description for ext',
  'category' => 'Example Extensions',
  'author' => 'Helmut Hummel',
  'author_email' => 'info@helhum.io',
  'author_company' => 'helhum.io',
  'shy' => '',
  'priority' => '',
  'module' => '',
  'state' => 'stable',
  'internal' => '',
  'uploadfolder' => '0',
  'createDirs' => '',
  'modify_tables' => '',
  'clearCacheOnLoad' => 0,
  'lockType' => '',
  'version' => '0.0.1',
  'constraints' =>
  array (
        'depends' =>
        array (
          'typo3' => '7.5.0-7.99.99',
        ),
        'conflicts' =>
        array (
        ),
        'suggests' =>
        array (
        ),
  ),
  'autoload' =>
  array(
        'psr-4' =>
        array(
          'Helhum\\ExtScaffold\\' => 'Classes'
        ),
        'classmap' =>
        array(
          'Resources/PHP/Libs'
        )
  )
);

In the example configuration the path Resources/PHP/Libs is parsed for PHP files which are automatically added to the class loader.

Impact

Extensions that target TYPO3 6.2 LTS and 7 LTS can now provide a class map in ext_emconf.php which is only evaluated in TYPO3 7 LTS and an ext_autoload.php which is only evaluated in 6.2 LTS for maximum flexibility and compatibility.