Cant you just deprecate the Old function, and remove it upon change ? If you mean 'keep bad behavior intact' (ie maintain bugs, that why you should have a spéci

Cant you just deprecate the Old function, and remove it upon change ? If you mean 'keep bad behavior intact' (ie maintain bugs, that why you should have a spécification. 'the implémentation is the spécification' is very bad imo