For now, packages' versions are based on the versions of the
distfiles, which is totally dependent on the original authors'
intension. That is, versions in DISTNAME do not always make sense for
Pkgsrc. IMO, PKGREVISION should be used _only_ if some changes
significant to Pkgsrc are made to a package while its DISTNAME doesn't
change. For example, a patch is provided instead of new distfile being
created.

Changes significant to Pkgsrc can't be fallen into these.

  * A package is not compatible any longer with the previous version.

  * The previous version must not be used any longer for a certain
    reason. E.g a vulnerability found in the previous one.

We should pay attention to the fact that packages' versions are
tightly related to pacckage dependency.

> This could entail API changes, integration of bugfix or functionality
> patches from a third party or development branch of the same package, or
> even changing the pathname of an executable.

IMHO, if a change is provided by a third party, it should not be the
"nbX" part to be bumped but the PKGNAME part.

> This would exclude such things as fixing typos in manpages, making a package
> build properly on a given architecture (where it would just bomb before --
> although if the fix entails changing real code, it'd be a bump)....

Bumping a PKGREVISION looks easy, but tracking version ups of other
packages may be hard.

Regards,
Masao

---                                                  \||v,
A Fish Lover,                                       /     \<
    Masao Uebayashi                               ((.),    |
        <uebayasi@soum.co.jp>                     ==__}|__ |
                                                   // \| |/
                                                        /|