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

[Peter Simons]

Hi Tobias,

 >> When such a situation has arisen in the past, it's my experience
 >> that the author of B typically releases an update to fix the issue
 >> with the latest version of C:
 >>
 >>   B 2.5.4.0 build-depends: C >= 3.8
 >>
 >> So that particular conflict does hardly ever occur in practice.
 >
 > And what if the maintainer of a takes the chance to make some major
 > updates and directly releases 2.6? Then all packages depending on
 > 2.5.* will probably break.

yes, that is true. In such a case, one would have to contact the
maintainer of A, B, and C to discuss how to remedy the issue.
Fortunately, pathological cases such as this one seem to happen rarely
in practice.

 > All this boils down to a system where only a combination of latest
 > versions will be stable. So why restrict dependencies anyway?

Now, I think that is an exaggeration. Do you know a single example of a
package on Hackage that actually suffers from the problem you're
describing?

Take care,
Peter