I have added a method foo to a class MYCustomClass in a category Category1 separate from the original definition of the class. Then I added another method also called foo in another category Category2. I then call foo on an instance of MYCustomClass. In my case the foo in Category2 is being called. My question is: Is there any explanation for this? Or, is it one of those “undefined”/”compiler dependent” behaviours. Also, is it possible to handle such situations by qualifying the method call by specifying the category I want to be used in the call.
EDIT: I am aware that what I am doing is not supported. I am just interested in if there is a hack around it.
When a category is loaded, its methods are inserted into the existing method table, and there’s no way to distinguish where they came from once that’s done. The last category to load wins. Back in the NeXTSTEP days, we would sometimes do this deliberately as a very kludgey way to fix a broken method in code for which we didn’t have the source.