GHC 7.8 release?

[Simon Peyton-Jones]

If there's a path to having a release strategy as Manuel suggests, and having an intermediate release  with the new vector primops, type extensions and such goodness, then I'm all for it.  A lot of these bits are things ill start using almost immediately in production / real software, esp if I'm not needing to patch every stable library beyond maybe relaxing versioning constraints.
Let me suggest once more a possible path, along the lines you suggest

·        For people who value stability: use the Haskell Platform.  Ignore GHC releases.

·        For people who want as many features as possible: use GHC releases.

·        For people who want to live on the bleeding edge: build HEAD from source


The Haskell Platform decides which GHC release to use, advertises that to package authors who do whatever updates are needed.  HP may perfectly sensibly skip an entire release entirely.

In short, I think we already have the situation that you desire.  Perhaps we just need to market it better?

Or am I mistaken?

Simon

From: Carter Schonwald [mailto:carter.schonwald at gmail.com]
Sent: 09 February 2013 02:45
To: Manuel Chakravarty
Cc: GHC Users List; ghc-devs at haskell.org; Andreas Voellmy; Simon Peyton-Jones; Edsko de Vries; Mark Lentczner; Johan Tibell; parallel-haskell
Subject: Re: GHC 7.8 release?


+10^100 to Johan and Manuel. Breaking changes on pieces that aren't experimental is the main compatibility / new version pain,

and I say this as someone who's spent time before and around the 7.4 and 7.6 releases testing out lots of major packages and sending a few patches to various maintainers.

If there's a path to having a release strategy as Manuel suggests, and having an intermediate release  with the new vector primops, type extensions and such goodness, then I'm all for it.  A lot of these bits are things ill start using almost immediately in production / real software, esp if I'm not needing to patch every stable library beyond maybe relaxing versioning constraints.

-Carter
On Feb 8, 2013 9:05 PM, "Manuel M T Chakravarty" <chak at cse.unsw.edu.au<mailto:chak at cse.unsw.edu.au>> wrote:
I completely agree with Johan. The problem is to change core APIs too fast. Adding, say, SIMD instructions or having a new type extension (that needs to be explicitly activated with a -X option) shouldn't break packages.

I'm all for restricting major API changes to once a year, but why can't we have multiple updates to the code generator per year or generally release that don't affect a large number of packages on Hackage?

Manuel

Johan Tibell <johan.tibell at gmail.com<mailto:johan.tibell at gmail.com>>:
On Fri, Feb 8, 2013 at 6:28 AM, Simon Marlow <marlowsd at gmail.com<mailto:marlowsd at gmail.com>> wrote:
For a while we've been doing one major release per year, and 1-2 minor releases.  We have a big sign at the top of the download page directing people to the platform.  We arrived here after various discussions in the past - there were always a group of people that wanted stability, and a roughly equally vocal group of people who wanted the latest bits.  So we settled on one API-breaking change per year as a compromise.

Since then, the number of packages has ballooned, and there's a new factor in the equation: the cost to the ecosystem of an API-breaking release of GHC.  All that updating of packages collectively costs the community a lot of time, for little benefit.  Lots of package updates contributes to Cabal Hell.  The package updates need to happen before the platform picks up the GHC release, so that when it goes into the platform, the packages are ready.

So I think, if anything, there's pressure to have fewer major releases of GHC.  However, we're doing the opposite: 7.0 to 7.2 was 10 months, 7.2 to 7.4 was 6 months, 7.4 to 7.6 was 7 months.  We're getting too efficient at making releases!

I think we want to decouple GHC "major" releases (as in, we did lots of work) from API breaking releases. For example, GCC has lots of major (or "big") releases, but rarely, if ever, break programs.

I'd be delighted to see a release once in a while that made my programs faster/smaller/buggy without breaking any of them.

-- Johan

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