sidedatacopies: get and store sidedata in the changelogrevision object The object provide a simple way to access changelog entry, we need it to also bear the sidedata value. Since the sidedata are retrieved at the same time as the revision, we can do that without extra cost. Differential Revision: https://phab.mercurial-scm.org/D6951

sidedatacopies: write copies information in sidedata when applicable If the format of the repository indicate it stores copies information into changeset's sidedata, then we actually write that information into sidedata at commit time. It will be put to use in later changesets. Currently, we store all field unconditionally, but that is likely to change in the future for the sake of efficiency. Differential Revision: https://phab.mercurial-scm.org/D6950

sidedatacopies: introduce a sidedata testcase for test-copies-in-changeset.t For now it is equivalent to the filelog case, but introducing this early helps make the comings changesets clearer. Differential Revision: https://phab.mercurial-scm.org/D6949

sidedatacopies: introduce a sidedata testcase for test-copies-unrelated.t For now it is equivalent to the filelog case, but introducing this early helps make the comings changesets clearer. Differential Revision: https://phab.mercurial-scm.org/D6948

sidedatacopies: introduce a sidedata testcase for test-copies.t For now it is equivalent to the filelog case, but introducing this early helps make the comings changesets clearer. Differential Revision: https://phab.mercurial-scm.org/D6947

sidedatacopies: teach upgrade about the new requirement The `debugformat` and `debugupgraderepo` command now detect the requirement. (upgrade to and from are not currently possible). Differential Revision: https://phab.mercurial-scm.org/D6946

sidedatacopies: add a new requirement for storing copies into sidedata The end goal is to have changesets centric sidedata information stored into changelog sidedata. This make it possible to use the changeset based copy tracing algorithm on any repository without affecting hashes. The actual implementation is coming. The feature is marked as experimental (do not use in production) until we stabilise details about the format. Differential Revision: https://phab.mercurial-scm.org/D6945

debugsidedata: small doc improvement The command has a mode to actually show the sidedata, but it wasn't documented. Differential Revision: https://phab.mercurial-scm.org/D6944

upgrade: allow for `sidedata` removal If the side-date feature is removed, we need to drop them. Differential Revision: https://phab.mercurial-scm.org/D6943

upgrade: allow upgrade to repository using sidedata Repository can now be migrated to support sidedata. More requirements and migration will be needed to actual side-data usage. This is a step in that direction. To test the feature, we leverage the test extension. It make sure the `update` part of the side-data migration actually works. Differential Revision: https://phab.mercurial-scm.org/D6942