Re: Mercurial "r####" numbers are not stable, use commit ids

No, reset (without a file argument) by default affects the index and HEAD and leaves the working tree alone. (The index is where the "add", "remove", and "to commit" state is stored, among other things.) The revision history itself is immutable except by "git gc --prune". "git reset --hard" is exactly equivalent to "hg update -C", I think.

So, for example if I do # make changes git commit -m "first" # make changes git commit -m "second" git tag tip git reset HEAD^ then the index ("git status", more or less) will show that I've got the changes in "second" in the workspace, but HEAD will point to the commit logged as "first", and a new commit will have the commit logged as "first" as its parent. If I use the "--soft" flag, then the index will show that all of those changes are staged for committing. Finally, I can do "git reset tip" and I'll be back where I started.

Do tags and branch points move too? I suspect not. (In git they don't move when you rebase, but I don't use rebase to emulate patch stacks in git.)