On Wed, Aug 15, 2012 at 03:54:04PM -0700, Michael Sloan wrote:
Upper bounds are a bit of a catch-22 when it comes to library authors evolving their APIs:
1) If library clients aren't encouraged to specify which version of the exported API they target, then changing APIs can lead to opaque compile errors (without any information about which API is intended). This could lead the client to need to search for the appropriate version of the library.
Having the version number A.B.*, than most packages seem to mostly increase B or lower parts of the version number. If an upper bound is missing, than cabal could use any package in the range A.*.* . If an author wants to make breaking changes to his API, than he could indicate this by increasing A. I've nothing against your proposal, I just don't think that it will be done that soon. Greetings, Daniel