Re: Rollback of git commands

From: Geert Bosch <bosch@adacore.com>
Date: Nov 28, 2007, 04:07 UTC
Message-ID: <3AAC5548-A9AC-4236-B1F7-5CFDE11B52C4@adacore.com>
In-Reply-To: <9e4733910711271749q1b96bfe9i60e43619c89234b9@mail.gmail.com>

On Nov 27, 2007, at 20:49, Jon Smirl wrote:

Show 5 quoted lines

> Rollback is too strong of name for this. Checkpoints would be better.
> The idea is to record the total system state at convenient moments and
> then allow moving back to the checkpointed state. The object store
> supports this, but the rest of the state in .git/* isn't being
> recorded.

I have always wondered why refs and tags are not in the regular object store. In a way, there should be just one root pointer (SHA1) pointing to a tree with refs, etc.

As for the problem of "lots of loose objects", each command could write a single pack file. By directly writing deltas instead of complete new tree objects, storage requirements should be modest. Also, just writing a single new pack file is very efficient for I/O purposes.

To prevent too many pack files, a merge policy could allow a new pack to include (and thus obsolete) a number of similarly sized or smaller packs. After the new file has been successfully written, the old files are no longer necessary and can be moved to a "trashes" area to be expired.

   -Geert