On Tue, 4 Nov 2025, Greg A. Woods wrote:
IIUC it's not usually normal CVS commands which are the problem (though using them incorrectly by accident is often a root cause of the problem). "cvs admin" is the one potentially risky one, though many of its dangers can be controlled by restricting which users are in the "cvsadmin" group -- i.e. limiting its use to experts who should know better.
In current usage of the NetBSD repo, no one goes behind CVS' back to edit the repo directly, and I think most people are scared of "cvs admin" for a good reason.
You missed another, unfortunately much more common operation that changes all older commit hashes: If you delete a file with a $NetBSD$ line in it, CVS will more its ,v file to the Attic subdirectory. It will then go back and retroactively rewrite all revisions of the file with the changed path to the ,v file including the word Attic.
-- Benny