Re: Haskell Platform call for consensus: add transformers and revise the mtl package to depend on it

On 11/03/10 03:39, Johan Tibell wrote:

On Wed, Nov 3, 2010 at 5:50 AM, Isaac Dupree wrote:

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mtl-2.0 was just recently uploaded. If it's easy, I would cautiously wish to wait a month before committing-for-sure to mtl-2 in the platform, and see if there are unexpected transition difficulties. Any issues that users notice will surely get mentioned on the mailing-lists. Though, the proposal page (and past experience with transformers/monads-fd) does seem to have investigated the difficulties pretty well; and if the difficulties are not much more than estimated, then they seem worth the costs to me.

We have about a month and a half to figure it out. During that time we'll try to migrate all HP packages to mtl-2 (and perhaps some other important packages.) If that doesn't cause problems, we can go ahead with mtl-2 in the next. Release, if it does cause problems, well then mtl-2 will not make it. Put another way, all accepted proposals are conditionally excepted on actually being possible to implement. :)

Right, IIRC we've done that in the past -- the "implementer's" role just wasn't explicitly acknowledged (in the sense that there's *always* a nontrivial chance that something can go wrong, and a corresponding "conditional acceptance" that we probably should acknowledge as such, rather than blame implementers for not being super perfect. Interesting.). (thinking aloud..) I realized this proposal is somewhere between "adding a package" and "upgrading a package". It adds transformers. But it also upgrades mtl. But mtl-2.0 didn't exist on Hackage at the time of the proposal -- because the proposal was the place to decide *whether* we want that to be the future of mtl. (Usually a package proposed for HP should exist on Hackage first, and this will lead to natural testing, compatibility-fixing, etc., already. Although when we accept a package on the condition of lots of API changes -- as we might do with 'text' -- this also lacks natural testing-time similar to the mtl-2.0 situation.)

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(Is there time pressure? Given http://trac.haskell.org/haskell-platform/wiki/ReleaseTimetable I am not sure. Incidentally it suggests that we technically missed the proposal deadline by one day depending on timezones - Nov 1 vs Nov 2 - which I'm not inclined to worry about. The page history says Don Stewart wrote that timeline mid-July.)

That's my (and the rest of the steering committee's) fault for not calling for consensus sooner when the discussion died out. My apologies.

Oh, you're quite right. I'd forgotten we made some roles that only steering-committee members can carry out ( http://trac.haskell.org/haskell-platform/wiki/AddingPackages ). I should know, because I *am* one of the steering committee! -Isaac