Re: Hey - A Conceptual Simplication....

[Dmitry Potapov <dpotapov@gmail.com>]

On Fri, Nov 20, 2009 at 03:35:40AM +0100, Björn Steinbrink wrote:
> On 2009.11.20 04:48:44 +0300, Dmitry Potapov wrote:
> > On Wed, Nov 18, 2009 at 09:03:31PM -0500, George Dennie wrote:
> > > 
> > > For example, the functional notion of the repository seems well
> > > defined: a growing web of immutable commits each created as either an
> > > isolated commit or more typically an update and/or merger of one or
> > > more pre-existing commits. 
> > 
> > In Git, commits are not immutable.
> 
> Commit _are_ immutable. Like all git objects (blob, tree, commits, tag).
> "Rewriting" history actually means creating a new history (adding
> objects), and then changing a ref (most often a branch head) to
> reference the new instead of the old history.

I stand corrected. All objects in Git repository are actually immutable,
but because references can be changed (and tools like git-rebase change
it automatically), it _appears_ like editing existing commits, but in
fact old commits do not disappear immediately. Even if there is no other
branches or tags that refer to old commits, git-reflog stores references
to them for 30 days after that the garbage collector can remove them.


Dmitry