Re: [RFC] undo and redo

On Wed, Aug 24, 2005 at 11:51:32AM -0700, Linus Torvalds wrote:

On Wed, 24 Aug 2005, Carl Baldwin wrote:

quoted

Oops.  I forgot to actually exit from the script if git-diff-files is
non-empty.

Also, looking at it now, I don't think keeping undo information in a
stack is the right thing.  But keeping more than just one would be good.
Oh well, my first shot is never perfect.  ;-)

I would actually argue that

	git checkout -b newbranch <undo-point>

is the perfect undo.

Yes, this does the job nicely.  I've used it like this effectively.  I
meant for undo/redo to be a lighter weight way of moving (uncommitted)
changes out of the way briefly and then replaying them onto the working
directory later.

It leaves the old state in the old branch, and creates a new branch (and
checks it out) with the state you want to revert to. The advantage is
exactly that there is no "stack" of undo's: you can have multiple
independent undo's pending, and you can continue development at any of 
them. And merge the results together.

The "stack" was the wrong thing to do.  I think I would have undo pick a
name like undo-1, undo-2 etc.  Or something like that.  redo would pick
the most recent unless told to do otherwise.

A possible advantage of undo is having the freedom to stay on the
current branch or switch to another.

Of course, right now we don't have a "delete branch" command, but it's 
really as simple as

	rm .git/refs/heads/branchname

(and eventually you may want to do a "git prune" to get rid of stale
objects, but that's a separate issue).

		Linus

This brings up a good point (indirectly).  "git prune" would destroy the
undo objects.  I had thought of this but decided to ignore it for the
time being.

Carl

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 Carl Baldwin                        Systems VLSI Laboratory
 Hewlett Packard Company
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