Manual:Extension registration/Limitations/en

Extension registration does have known limitations that may make it unsuitable to convert your extension immediately. Some of these are intentional, and others are just waiting for a developer to implement them :)


 * Configuration settings must have a prefix of "wg" resolved, use a magic "_prefix" key : T97186
 * PHP constants are not supported. The rationale for this is constants are either used in LocalSettings.php when raw strings should be used instead (you can't use constants in a configuration database), or in code, when they should instead be a part of a class.
 * You can't use paths to files in extension.json: ???
 * Conditional namespaces are not supported: ???

The workaround for much of this is to use custom registration. If you find something you can't do, create a Phabricator task.