Re: [Haskell-cafe] How to determine correct dependency versions for a library?

* Erik Hesselink [2012-11-10 16:40:30+0100]

On Fri, Nov 9, 2012 at 5:52 PM, Roman Cheplyaka wrote:

...

* Janek S. [2012-11-09 17:15:26+0100]

...

but I am aware that if the library were to be released on Hackage I would have to supply version numbers in the dependencies. The question is how to determine proper version numbers?

With the current state of affairs, your best bet is not to specify any version bounds, or specify only lower ones.

Upper version bounds much more often break things that fix things.

I'd like to ask people not to do this. What you're doing then is moving the burden from the maintainer (who has to test with new versions and relax dependencies) to the users of the library (who will be faced with breakages when new incompatible dependencies are released).

The trouble is, when things break, they break either way — so I simply propose to reduce the probability of things breaking. I know, I know, the theory is that Cabal magically installs the right versions for you. However, in practice it often can't do that due to various reasons (base libraries, package reinstalls etc.) I'm not trying to shift the burden from the maintainer — I simply know from experience that maintainers are not nearly as quick and responsible as would be required for such scheme to work, so as a *user* I'd prefer that they omit upper bounds — at least until the --ignore-constraints option is implemented. (https://github.com/haskell/cabal/issues/949) Roman