qualified imports, PVP and so on

Herbert Valerio Riedel hvr at gnu.org
Tue Feb 25 22:52:23 UTC 2014

On 2014-02-25 at 21:38:38 +0100, Michael Snoyman wrote:


> * The PVP itself does *not* guarantee reliable builds in all cases. If a
> transitive dependency introduces new exports, or provides new typeclass
> instances, a fully PVP-compliant stack can be broken. (If anyone doubts
> this claim, let me know, I can spell out the details. This has come up in
> practice.)

...are you simply referring to the fact that in order to guarantee
PVP-semantics of a package version, one has to take care to restrict the
version bounds of that package's build-deps in such a way, that any API
entities leaking from its (direct) build-deps (e.g.  typeclass instances
or other re-exported entities) are not a function of the "internal"
degree of freedoms the build-dep version-ranges provide? Or is there
more to it?

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