Subversion-style incrementing revision numbers

Hello, all.

I'm considering adopting Git for a medium-sized project which is currently managed using Subversion. I've used Git for a few smaller projects already, and the thing I've missed most from Subversion is the convenience of incrementing revision numbers. The following is a proposal to add this feature to Git.

Rationale:

Incrementing revision numbers (IRNs - an acronym I just made up) are useful in that they can be treated as auto-generated tags which are easier to remember and communicate than SHA hashes, yet do not require extra effort to create like real tags. Also, they have the advantage of being chronologically ordered, so if I assert that a bug was fixed in revision 42 of a shared repository, everyone may assume that revision 45 has that fix as well.

Proposal:

As with Subversion, the IRN state in Git would be specific to a given repository and have no significance beyond that repository. Also like Subversion, IRN state would be global across a repository, so that a commit to any branch would increment the current IRN value. Every Git command taking a revision parameter would accept an IRN using a syntax such as "r$IRN". Every commit would report the IRN to the user as well as the SHA ID. The IRN feature could be enabled or disabled via a configuration option.

Implementation:

A simple, efficient implementation of this feature would be based on a single file, $GIT_DIR/history, which would contain a newline-delimited list of SHA commit IDs in chronological order, oldest first. The current repository IRN would be calculated as the size of that file divided by the SHA+newline length, and the commit ID of any IRN could be determined by seeking to the correct offset in that file. Every commit would cause a new line to be appended to the history file with that commit's ID. Finally, a history file could be generated for an existing repository by serializing the commit history based on chronological order.

I'd be happy to put together a patch that implements this, but first I'd like to get some feedback. If something like this has already been proposed, please point me to the discussion. Thanks.

  - Joel