Relaxin the PVP with regards to adding instances

Erik Hesselink hesselink at
Thu Sep 6 09:27:59 CEST 2012

On Thu, Sep 6, 2012 at 7:01 AM, Michael Sloan <mgsloan at> wrote:
> Thing is, that if this is the design goal of the PVP, then _any_
> addition to the exports of a module should necessitate a major version
> bump, because of the potential for clashing unqualified, non-explicit
> imports.  The reasoning for this seems to be that the chances are low
> (very context dependent) and unqualified, non-explicit imports are
> discouraged and bad style.  Orphan instances are also discouraged, so
> for consistency with the policy for regular additions, it would make
> sense for libraries adding instances to only necessitate a minor
> version bump.

No, the PVP explicitly mentions this. An added export needs only a
minor version bump. A user of the package can then:

 * Depend on only the range of bugfix releases (A.B.C.*), thus
guarding against additions. Or,
 * Depend on a range of minor versions (A.B.*), and use only explicit
or qualified imports, again guarding against additions.


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