[Haskell-cafe] Fwd: Fwd: Compatibility etiquette for apps, with cabal sandboxes and `stack`
jo at durchholz.org
Mon Nov 30 08:54:13 UTC 2015
Am 30.11.2015 um 08:20 schrieb Sven Panne:
> Personally, I don't consider littering my code with version numbers as
> "little effort".
Indeed it isn't.
The effort could be reduced with proper tool or language support.
> Stuff like this should be specified outside of the source
> code IMHO.
Let's assume semantic versioning: major version number changes for
incompatible API changes, minor for downwards-compatible API changes,
and tertiary ("milli") version number changes for API-unaffecting changes.
So if your code calls into foo-3.4.1, you shouldn't have to worry
whether it is actually being used with foo-3.4.2, or foo-3.5.0.
However, you need to say foo-3 somewhere, inside your sources, because
your code may break with foo-4.x.x.
One issue I'm having with semantic versioning is that
supposed-to-be-compatible library updates tend to be actually
incompatible, often in subtle ways, so the library is released with a
millversion change but that's a mistake (and lieing towards the
application that's assuming an unchanged API).
It's a big issue with imperative languages, where implementation details
can leak via state. In Haskell, I suspect that (non-)termination
behaviour is a similar potential implementation leak, though there's
less opportunity for that to actually happen since the library would
need to have lots of complicated, potentially infinite data structures
hidden below opaque types.
More information about the Haskell-Cafe