Re: Proposal: Add exception info

I'm +1 on this proposal. On 21-04-2015 12:52, Michael Snoyman wrote:

On Tue, Apr 21, 2015 at 5:56 PM Yitzchak Gale mailto:gale@sefer.org> wrote:

Michael Snoyman wrote: > Can you give an example of a concrete problem you're > expecting to run into?

Package foo uploads a new version with a critical bug fix. As is often the case, this new version also supports updated dependencies, including exceptions. The new exceptions breaks the old SomeException type, so foo is forced to specify a lower bound that excludes the old exceptions.

But that's the scenario I'm asking for more information on. Can you clarify what you're describing here? I'm not seeing a situation where an author couldn't easily be compatible with GHC <=7.8 by sticking to the old API?

I think Michael Gale is thinking about an author that may end up using the new SomeExceptionWithInfo constructor for some reason, thus leaving older GHCs out of any new updates. However, IIUC, this would cause problems for GHC < 7.12, not only GHC < 7.10, since you won't be able to use GHC 7.12's base package on GHC 7.10. So perhaps I'm misunderstanding the issue as well. Cheers, -- Michael Lessa.