localrepo: eliminate requirements class variable (API) Localrepo's requirements class variable was introduced in b090601a80d1 to make requirements modifiable by extensions. A main access point, _baserequirements, still exists, but this change undoes making the class variable to begin with. Without this simplification, there is a class variable with a default value that is only copied, but never directly used. This behavior is moved directly into the _baserequirements function.

changegroup.group: drop 'reorder' parameter Since we always pass self._reorder to self.group(), let's drop the parameter and let group() read from self._reorder itself. There are no other in-tree callers to group().

cg2packer: set reorder=False in __init__ instead of in group() The difference between reorder=None (bundle.reorder=auto) and reorder=False is that the generaldelta revlogs get reordered with the former. In cg2packer, group() we check if the revlog uses generaldelta and if reorder=None and then convert that to reorder=False. We are effectively saying that whether or not generaldelta is used, we want reorder=None to mean reorder=False for changegroup 2. To make this clearer, check if reorder=None in the constructor and change it to False there and drop the overriding of group(). Also document the reason for turning reordering off.

changegroup: use 'reorder is None' instead of 'reorder is not True/False' The config option bundle.reorder can be {on,off,auto}, which gets read into the 'reorder' variable as {True,False,None}. In two places, we need to decide how to handle the None/auto case. I personally find it easier to read those expressions when written to explicitly compare to None.