revlog: introduce a `sidedata` method
The method give access to extra information related to the revision. Such data
will not be part of the hash be strongly related to the revision. Having them
stored at the revlog level helps the storage consistency story and simplify
various things.
Example of data we could store there:
- copy tracing related informations
- graph structure related information (useful for discovery)
- unresolved conflict data
The full implementation will be introduced gradually in the coming changesets.
Differential Revision: https://phab.mercurial-scm.org/D6808
Mercurial
=========
Mercurial is a fast, easy to use, distributed revision control tool
for software developers.
Basic install::
$ make # see install targets
$ make install # do a system-wide install
$ hg debuginstall # sanity-check setup
$ hg # see help
Running without installing::
$ make local # build for inplace usage
$ ./hg --version # should show the latest version
See https://mercurial-scm.org/ for detailed installation
instructions, platform-specific notes, and Mercurial user information.