Extend RootPackageInterface with setter functions used by
composer-merge-plugin and implement them for RootAliasPackage. This will
allow composer-merge-plugin and similar code that manipulates the root
package at runtime to ignore the difference between a RootPackage and
a RootAliasPackage.
AliasPackage caches the values of 'requires', 'devRequires',
'conflicts', 'provides', 'replaces' locally to allow `self.version`
references to be properly updated to reference the alias. Plugins like
composer-merge-plugin that manipulate these settings at runtime need to
be able to change the values after alias construction.
Jordi Boggiano
Michael Telgmann
Sven Wittevrongel
Bryan Davis
Vadim Tyukov