hg-stable: Changelog

copies: make two version of the changeset centric algorithm They are two main ways to run the changeset-centric copy-tracing algorithm. One fed from data stored in side-data and still in development, and one based on data stored in extra (with a "compatibility" mode). The `extra` based is used in production at Google, but still experimental in code. It is mostly unsuitable for other users because it affects the hash. The side-data based storage and algorithm have been evolving to store more data, cover more cases (mostly around merge, that Google do not really care about) and use lower level storage for efficiency. All this changes make is increasingly hard to maintain de common code base, without impacting code complexity and performance. For example, the compatibility mode requires to keep things at different level than what we need for side-data. So, I am duplicating the involved functions. The newly added `_extra` variants will be kept as today, while I will do some deeper rework of the side data versions. Long terms, the side-data version should be more featureful and performant than the extra based version, so I expect the duplicated `_extra` functions to eventually get dropped. Differential Revision: https://phab.mercurial-scm.org/D9114

changing-files: retrieve changelogrevision.files from the sidedata block The `files` field is know to have issue, using a list with fixed, and fixable, computation can only help. For example, using a fixes `files` field would be enough to fix issue6219 once this feature get usable in production. We focus on having thing working for now, we will deal with performance later. Right now we have a ironic situation were we parse sorted value from disk to turn them into a set and then having to sort it again. Differential Revision: https://phab.mercurial-scm.org/D9092