Some rant about general VCS requirements which will ideally end in a formal model matching mercurial implementation (with hope it's not totally out of topic on the mercurial wiki).

See this page as a pure intellectual exercise for now.

Requirements

Express from coarser detail to finer detail.

High level requirements

• Manage objects (will be files, directory, metadata...)
  • add object
  • remove object
  • modify object
• keep immutable history (except for obliterating some content ?)
• restore state from the past

Intermediate level requirements

• keep trace of who did the object management actions
• add property to objects (comment, date, author..)
• add property to history state (tags ?)

Distributed requirements

• Local history (will end in repository / branches)
  • clone
  • merge

Other secondary requirements

• narrow/shallow cloning ?

Low levels requirements

Map to mercurial commands/functions:

• init, add, remove, backout, branch, clone, commit, copy, move, merge, push, pull, revert, tag

Map to mercurial internals:

• manifest, revlogs,

Formal Method

• B event (via rodin platform)