Keep Interface New Argument Compatible

By Jerome Tamarelle

A reminder for maintainers of PHP libraries: adding a parameter to a method of an interface causes a fatal error in all the classes that implement it. It’s a BC break that should be prohibited in a minor version.

In Symfony, we add the parameter virtually using phpdoc, and read it using func_get_arg().

See Also

• Original BluSky

• func_get_arg

• Example code [Try me]

PHP Features

• compatibility

• method-compatibility

• version