[ghc-steering-committee] GHC 2020
Simon Peyton Jones
simonpj at microsoft.com
Mon Oct 19 07:21:57 UTC 2020
Some thoughts
* I'm willing, but not truly enthusiastic, about the whole idea.
The reason I'm willing is because I believe that the community really
wants it -- but I'd love to have evidence for that belief. This
discussion is taking place on the GHC committee mailing list to which
the community more broadly can't easily contribute. I'd love to ask
them more explicitly, or even take a poll.
* Do we really want to an annual process? My personal thought is
that every two or three years would be plenty often enough. Having
a plethora of extensions is confusing. "Is Polykinds in GHC2023?"
* When it comes to individual extensions, I'd like to know what the community
thinks, since a lot of this is about convenience and stability. I'd
suggest a poll of Haskell users. Their votes might guide the committee
-- but would not determine the outcome.
* I would also suggest that the process be informed by a trawl of Hackage/Stackage
to count how widely used each extension is. That is, seek data as well as opinion.
* Joachim's 2/3 supermajority seems sensible. An extension should only
make it in if there is solid support.
Simon
| -----Original Message-----
| From: ghc-steering-committee <ghc-steering-committee-
| bounces at haskell.org> On Behalf Of Joachim Breitner
| Sent: 18 October 2020 22:01
| To: ghc-steering-committee at haskell.org
| Subject: Re: [ghc-steering-committee] GHC 2020
|
| Hi,
|
| Am Samstag, den 17.10.2020, 21:26 +0200 schrieb Alejandro Serrano Mena:
| > I would really like this effort not to die, so I've given the
| > proposal another push. Following the comments from Simon and Joachim,
| > I've re-framed the proposal as laying down a process to create new
| > "language versions" yearly. The idea is to have one of these every
| > year (or 2, or 3, whatever is decided), coinciding with the spring
| > release of GHC.
| >
| https://nam06.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithu
| b.com%2Fserras%2Fghc-proposals%2Fblob%2Fghc-2020%2Fproposals%2F0000-
| ghc-
| 2020.md&data=04%7C01%7Csimonpj%40microsoft.com%7Cbdddd9d809644bd069
| 9f08d873a8f25d%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C63738651681
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| BTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=gw0IAOeYqR7PwypWK4KuGs%2Bg
| pFwJB8wvBxWULqIqFes%3D&reserved=0
|
|
| I like the idea of tying this to the Spring release of GHC, this
| provides a lot of predictability, and also provides a hard deadline,
| which makes it more likely to make _some_ progress (instead of never
| achieving the perfect set of extensions).
|
| To questions about the criteria:
|
|
| If GHC2021 contains extension Foo, I assume that by default, GHC2020
| also contains Foo. But should we allow ourselves to remove something?
| (I would argue, yes: it should be a rare thing, but if Foo turned out
| to be problematic, then it seems better to not include it in the next
| version. Code that still declares 2021 wouldn’t be affected, and code
| that wants to use GHC2021 and Foo would have to list Foo explicitly,
| which is arguably a good thing.)
|
|
| Should we make it a hard rule that the extension needs to be supported
| by the last _n_ versions of GHC?
| (Would we maybe make point releases of prior versions of GHC to
| understand -XGHC2021, to make these sets of extensions available to
| more users faster?)
|
|
| > I think it's important for the community to be involved in the
| > process. If it's clear that an extension is loved by most of the
| > community, that's a big plus for acceptance. In addition, if we come
| > with a list ourselves, we risk having made choices which only show
| > our (biased) point of view.
|
| I would hope that with 10 people on the committee, the bias is not too
| big. And just like GHC proposals that attract discussions are sent back
| as “needs review”, extensions that cause non-trivial discussion are, by
| definition, not uncontroversial enough, and should simply be “maybe
| next year”.
|
| Therefore I would like to start with a slimmer, more effective and
| efficient process that does not involve a full proposal-size discussion
| on each extension, and does _not_ cause dozends of parallel discussions
| with the community. So here is a first draft of the “slim proceess”:
|
| =============================================================
|
| * 4 months before the expected GHC spring release day of 202x:
| The Secretary starts the GHC202x process. with an email to the list
| listing all language extensions supported by GHC that are not in
| GHC202(x-1), and asking the committee for “votes” (which are also
| nominations).
|
| The secretary also creates a PR with a proposal saying (roughly)
| > GHC202x contains the following extensions in addition to those
| > in GHC202(x-1):
| >
| > * (none yet)
|
| The community may use comments on this PR to weigh in.
|
| * Within two weeks of the start of the process,
| every committee member is expected to send an
| initial list of which extensions they expect to be in GHC202x
| to the mailing list. These mails may contain justifications
| for why a certain extension is or is not included.
|
| After these two weeks, the PR is continuously updated by the
| secretary to reflect the _current_ tally of votes:
| An extension is included if it is listed by at least ⅔ (rounded up)
| of committee members.
|
| * Within four weeks, of the start of the process,
| committee members can change their vote (by email to the list).
|
| It is absolutely ok to change your mind based on the explanations in
| the other members’ emails, or the general comments on the PR.
|
| * After these four weeks, the proposal with the current tally
| gets accepted, and defines GHC202x
|
| =============================================================
|
| The goal here is, of course, to efficiently find out which are the
| uncontentious extensions, without spending a log of time on the
| contentious ones (which I think we simply want to continue to guard
| behind their own explicit extension).
|
|
| Meta-process comments:
| I’ll turn this into an alternative PR to Alejandro’s once he opened
| his, and we can vote on both together (using ordered voting, I still
| prefer Alejandro’s process to no GHC2021, this way we don’t step on
| each other’s toes).
|
|
|
| > Since in the first round the possible list of extensions may be quite
| > big, we might introduce a "fast-lane process" for this one time, for
| > extensions like EmptyDataDecls or different number formats which seem
| > to have unanimous support.
|
| I guess I agree, and I’d just make that the only process :-)
|
| Cheers,
| Joachim
| --
| Joachim Breitner
| mail at joachim-breitner.de
|
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