Feature: #108345 - Allow extensions without ext_emconf.php in classic mode 

Extension title 

See Feature: #108653 - Database storage for form extension for how the extension title can also be set in composer.json.

The version number can be set in the regular "version" field in composer.json.

Extension version 

For third-party extensions to be compatible with TYPO3 classic mode, this field must now be set to the exact version previously defined in ext_emconf.php and must match the version in the Git tag (for example, when publishing to Packagist).

Fixture extensions used in tests can set any version number, for example 1.0.0, but a version number must still be provided to avoid deprecation messages. During testing, the version number is not evaluated.

TYPO3 Core extensions may omit the version number in composer.json, because their version can and will be derived from php\TYPO3\CMS\Core\Information\Typo3Version.

Dependencies on other TYPO3 extensions 

ext_emconf.php had a property for specifying dependencies on other extensions by referencing the extension key and, optionally, a version range.

composer.json also contains a field for specifying dependencies by using a Composer package name with a version range. However, there is no direct way to distinguish whether such a package name refers to another TYPO3 extension or to a regular Composer package that should be installed from Packagist.

TYPO3, however, needs to know which other extensions an extension depends on in order to resolve the extension loading order correctly.

Therefore, TYPO3 must know which package names refer to extensions and which do not. In Composer mode, this can be resolved automatically.

In classic mode, extensions must specify which package names in the require section of composer.json are regular Composer packages. All other package names in the require section are assumed to be TYPO3 extensions.

Because of this, extension authors who want their extensions to be compatible with TYPO3 classic mode and whose extensions have dependencies on Composer packages must also specify which Composer packages they provide when loaded in classic mode.

This is done by specifying which Composer packages the extension provides in classic mode.

Here is an example:

Before:

{
    "name": "vendor/example",
    "type": "typo3-cms-extension",
    "description": "example",
    "license": "GPL-2.0-or-later",
    "require": {
        "typo3/cms-core": "^14.2",
        "vendor/other-example": "*",
        "symfony/dotenv": "^8.0"
    },
    "extra": {
        "typo3/cms": {
            "extension-key": "example_extension"
        }
    }
}

After:

{
    "name": "vendor/example",
    "type": "typo3-cms-extension",
    "description": "example",
    "version": "1.0.0",
    "license": "GPL-2.0-or-later",
    "require": {
        "typo3/cms-core": "^14.2",
        "vendor/other-example": "*",
        "symfony/dotenv": "^8.0"
    },
    "extra": {
        "typo3/cms": {
            "extension-key": "example_extension",
            "Package": {
                "providesPackages": {
                    "symfony/dotenv": ""
                }
            }
        }
    }
}

In this example, the Composer package names typo3/cms-core and vendor/other-example are assumed to refer to TYPO3 extensions, and TYPO3 guarantees that vendor/example is loaded after vendor/other-example. Otherwise, an error is thrown if the extension vendor/other-example does not exist in the system.

As before, extensions still need to find an appropriate way to ship Composer packages and determine when to require the autoloader for them.

Even if an extension does not depend on any Composer packages, it is still required to specify providesPackages in composer.json to ensure future compatibility with TYPO3 classic mode and to avoid deprecation messages in TYPO3 v14.

{
    "name": "vendor/example",
    "type": "typo3-cms-extension",
    "description": "example",
    "version": "1.0.0",
    "license": "GPL-2.0-or-later",
    "require": {
        "typo3/cms-core": "^14.2",
        "vendor/other-example": "*"
    },
    "extra": {
        "typo3/cms": {
            "extension-key": "example_extension",
            "Package": {
                "providesPackages": {}
            }
        }
    }
}

Be aware that keeping ext_emconf.php, while no longer directly required by TYPO3, may still be necessary for some tools, such as Tailor or TYPO3 TER. Therefore, for the time being, it is recommended to keep the file and ensure that its information stays in sync with composer.json as outlined above.

However, TYPO3 will not evaluate ext_emconf.php any more if the version field and providesPackages are correctly defined in composer.json.