Version Control Refactoring

This branch is a sandbox for introducing new features that are potentially disruptive.

This is based on the previous refactoring and on the TracDiff branch, both of them pretty much stable and already integrated in the trunk for milestone:0.10.

The forthcoming changes aim to be better support some advanced version control system backends, like ​Mercurial. To that effect, the changes added to the core will be exercised by jointly developing the TracMercurial plugin.

See also the related ​thread on the Trac Devel mailing list.

Support for Multiple scopes within a Repository

• This basically means fixing #1830. Initial work on this in r2992.
• There's also the idea to "scope" a repository using multiple paths. This will probably be done for milestone:0.11.

Support for Multiple Repositories

See #2086. See also ​this mail.

This will also probably be done for 0.11.

Support for Mercurial-like Version Control System

Basic Level

• DONE
  • support for non-numerical changesets (start with hexadecimal digit support)
  • support for extra changeset properties
    • basic infrastructure in trunk
    • support for SVN: see #2545

Those are the minimal changes needed so that the Mercurial plugin can work at all.

Advanced Level

• Support for direct jump to a tag or a branch. Done on the branch; not yet ported to trunk.
• DONE
  • Support for arbitrary changeset names (e.g. [tip] or [head])

Support for Big Repositories

This means extended cache support, and certainly needs some big changes to the way caching is done. Support for multiple repositories would also require some changes to the caching anyway.

This is material for Trac 0.11