Bug#891216: Requre d-devel consultation for epoch bump

[Ian Jackson <ijackson@chiark.greenend.org.uk>]

Package: debian-policy
Version: 4.1.3.0

We had another thread on debian-devel recently, in which it once again
became evident that epochs are misunderstood.  Epoch bumps should be
rare and there are often better solutions.  I suggest that we should
ask people to consult debian-devel.

Also we should encourage the +really convention rather than epoch
bumps.

Concretely,

    epoch

	This is a single (generally small) unsigned integer. It may be
	omitted, in which case zero is assumed. If it is omitted then the
	upstream_version may not contain any colons.
  -
  -     It is provided to allow mistakes in the version numbers of older
  -     versions of a package, and also a s previous version numbering
  -     schemes, to be left behind.
  -     package
  +
  +     Epochs can help when the upstream version numbering scheme
  +     changes, but they must be used with care.  In Debian, please
  +     consult debian-devel when changing the epoch.

  ...

    Note that the purpose of epochs is
  - to allow us to leave behind mistakes in version numbering, and
    to cope with situations where the
  + upstream
    version numbering scheme changes
  + and to allow us to leave behind serious mistakes
    .
  +
  + Epochs should not usually be used when
  + a package needs to be rolled back (use the +really convention)
  + or to
    cope with
  - It is not intended to
    version numbers containing strings of letters which the package
    management system cannot interpret (such as ALPHA or pre-), or with
    silly orderings.
  +
  + If you think that increasing the epoch is the right situation,
  + please consult debian-devel before doing so
  + (even in experimental).

Ian.