Rolling back
------------

- go to .../contrib/Archive/pkgname, find the latest version there,
  cross-check it is earlier than the currently published version and
  CRAN-pack it.

That will put the current version into the Archive, hence the need to
be careful if the package has previously been rolled back.

- Reomve the symlink in .../contrib to the previous version, and run
  CRAN-package-list.

- I often add an X-CRAN-History note to PACKAGES.in as to what was done and why.

- 'touch' the newly re-published tarball.

- Inform people doing checks (CRAN and perhaps individually Simon,
  Tomas and Uwe) that it has been rolled back.  Some of my scripts
  will notice a newer tarball date, but in other cases I need to
  manually reinstall the package.

Rolling back is best done immediately.  This might avoid binary
packages being published, and avoid other submissions/updates being
published which depend on the new version (rare, but has happened).
However, it removes any check results from the new version (and the
submissions team might forget about them if no errors are showing on
the currently published checks).