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