commands.push: use "pushloc" path attribute Path instances now have a "pushloc" attribute that exposes the path to be used for pushing. The "default-push" path is automatically captured in the "pushloc" attribute of the "default" path. Drop references to "default-push" and use the "pushloc" attribute for looking up where to push to.

ui: capture push location on path instances Currently, we treat "default" and "default-push" as separate paths, even though they are the same logical entity but with different paths for different operations. Because they are the same entity and because we will eventually be implementing an official mechanism for declaring push URLs for paths, we establish a "pushloc" attribute on path instances. We populate this attribute on the "default" path with the "default-push" value, if present. This will enable consumers stop referencing "default-push" which will make their code simpler.

worker: use multiprocessing to find cpu count The multiprocessing package was added in Python 2.6. The implementation of worker.countcpus() is very similar to multiprocessing.cpu_count(). Ditch our one-off code. multiprocessing does result in a number of imports. However, the lazy importer ensures that we don't import anything until cpu_count() is called. Furthermore, if we are doing something with multiple cores, chances are the time of that operation will dwarf the import time, so module bloat isn't a concern here.

import-checker: ensure multiprocessing is treated as from stdlib On my linux machines multiprocessing appears to defeat the logic in import-checker to detect stdlib modules. Since we now only use versions of Python which ship with multiprocessing, let's just whitelist the module.

reachableroots: use baseset lazy sorting smartset sorting is lazy (so faster in some case) and better (informs that the set is sorted allowing some optimisation). So we rely on it directly. Some test output are updated because we now have more information (ordering).

baseset: keep the input set around Baseset needs a list to operate, but will convert that list back to a set for membership testing. It seems a bit silly to convert the set into a list to convert it back afterward.