[Haskell-cafe] Platform Versioning Policy: upper bounds are not our friends

[Brandon Allbery]

On Fri, Aug 17, 2012 at 4:35 PM, Bryan O'Sullivan <bos at serpentine.com>wrote:

> Any vastly more complicated and detailed versioning scheme has a huge
> burden to prove that it won't collapse dramatically more quickly. (Frankly,
> I think that anything involving "specify every detail of your known
> dependencies" is dead on arrival from a practical standpoint: it's way too
> much work.)
>

If you do it in terms of hashed signatures, you can make the compiler and
toolchain do the work for you.  The problem with version numbers is that it
*is* manual.  It can't catch behavioral changes, though; you probably need
some kind of epoch override for that in the case where it doesn't come with
corresponding API changes.

The reason it's never done is that you can't really do it with C or C++.
 We can mostly avoid that (the FFI is an issue, but it is anyway:  cabal
can't really check C stuff, unless you use pkg-config which was two
operating modes:  exact versions or no versioning).

-- 
brandon s allbery                                      allbery.b at gmail.com
wandering unix systems administrator (available)     (412) 475-9364 vm/sms
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