localrepo: move new repo requirements into standalone function (API) This patch extracts the code for determining requirements for a new repo into a standalone function. By doing so, future code that will perform an in-place repository upgrade (e.g. to generaldelta) can examine the set of proposed new requirements and possibly take additional actions (such as adding dotencode or fncache) when performing the upgrade. This patch is marked as API because _baserequirements (which was added in b090601a80d1 so extensions could override it) has been removed and will presumably impact whatever extension it was added for. Consumers should be able to monkeypatch the new function to achieve the same functionality. The "create" argument has been dropped because the function is only called in one location and "create" is always true in that case. While it makes logical sense for this code to be a method so extensions can implement a custom repo class / method to override it, this won't actually work. This is because requirements determination occurs during localrepository.__init__ and this is before the "reposetup" "callback" is fired. So, the only way for extensions to customize requirements would be to overwrite localrepo.localrepository or to monkeypatch a function on a module during extsetup(). Since we try to keep localrepository small, we use a standalone function. There is probably room to offer extensions a "hook" point to alter repository creation. But that is scope bloat.

localrepo: isolate requirements determination from side effects In preparation for moving requirements determination to its own function.