Re: GHC 7.8 release?
Simon Peyton-Jones simo...@microsoft.com: 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? There is one kink: for GHC releases to be *useful* substitutes for the HP for people who want medium stability, they must not change (expect maybe add to) the APIs in GHC versions that do not coincide with HP releases. Why? If they change APIs, many of the packages on Hackage will not build with these intermediate GHC releases, which makes them useless for anything, but testing GHC. Otherwise, I am perfectly happy with your suggestion. However, this is not the status quo. All (major) GHC releases do break critical packages on Hackage. Manuel ___ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
Re: GHC 7.8 release?
Simon Marlow marlo...@gmail.com: I agree too - I think it would be great to have non-API-breaking releases with new features. So let's think about how that could work. Some features add APIs, e.g. SIMD adds new primops. So we have to define non-API-breaking as a minor version bump in the PVP sense; that is, you can add to an API but not change it. As a straw man, let's suppose we want to do annual API releases in September, with intermediate non-API releases in February. Both would be classed as major, and bump the GHC major version, but the Feb releases would only be allowed to bump minor versions of packages. (except perhaps the version of the GHC package, which is impossible to keep stable if we change the compiler). So how to manage the repos. We could have three branches, but that doesn't seem practical. Probably the best way forward is to develop new features on separate branches and merge them into master at the appropriate time - i.e. API-breaking feature branches could only be merged in after the Feb release. Thoughts? That sounds sensible to me. Related to this, then, is the management of branches, which, I think, we can improve in two ways: (1) Make all library packages into submodules. (2) Fork-instead-of-branch and use GitHub pull requests. Re (1): submodules make tracking of synchronised branches across multiple repos simpler. Yes, they also have their pitfalls, but given that we are already using submodules extensively, we need to deal with those pitfalls anyway. So, why not reap the benefits, too? Re (2): we should encourage contributors to fork the GHC repos on GitHub and work in those. That makes it easy for everybody to build forks (which will be longer-lived under the above policy) and creating a fork doesn't require any special privileges in GHC repos. Finally, we can use GitHub pull requests to track contributions that are pending integration. This is IMHO also much nicer than attaching patches at Trac tickets. Manuel On 09/02/13 02:04, Manuel M T Chakravarty 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.tib...@gmail.com mailto:johan.tib...@gmail.com: On Fri, Feb 8, 2013 at 6:28 AM, Simon Marlow marlo...@gmail.com mailto:marlo...@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 -- You received this message because you are subscribed to the Google Groups parallel-haskell group. To unsubscribe from this group and stop receiving emails from it, send an email to parallel-haskell+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out. ___ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
Re: GHC 7.8 release?
Although it will definitely solve all problems, it would help if hackage would automatically send out mails to maintainers of packages which do not compile with specific ghc versions. I have ran a couple of time into the situation where new GHC releases did nor compile my packages anymore, and I only found out by this being pointed out to me. I do not go over the hackage pages of my packages on a daily basis. The changes I had to make were usually minor, and fixing the problems was easy (except for the case where I had to a add a complicated local type, when let bindings were no longer polymorphic), Doaitse On Feb 10, 2013, at 10:50 , Manuel M T Chakravarty c...@cse.unsw.edu.au wrote: Simon Peyton-Jones simo...@microsoft.com: 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? There is one kink: for GHC releases to be *useful* substitutes for the HP for people who want medium stability, they must not change (expect maybe add to) the APIs in GHC versions that do not coincide with HP releases. Why? If they change APIs, many of the packages on Hackage will not build with these intermediate GHC releases, which makes them useless for anything, but testing GHC. Otherwise, I am perfectly happy with your suggestion. However, this is not the status quo. All (major) GHC releases do break critical packages on Hackage. Manuel -- You received this message because you are subscribed to the Google Groups parallel-haskell group. To unsubscribe from this group and stop receiving emails from it, send an email to parallel-haskell+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out. ___ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
Re: GHC 7.8 release?
* Manuel M T Chakravarty c...@cse.unsw.edu.au [2013-02-10 21:17:07+1100] Re (2): we should encourage contributors to fork the GHC repos on GitHub and work in those. That makes it easy for everybody to build forks (which will be longer-lived under the above policy) and creating a fork doesn't require any special privileges in GHC repos. Finally, we can use GitHub pull requests to track contributions that are pending integration. This is IMHO also much nicer than attaching patches at Trac tickets. FYI, it is also possible to create pull requests from one branch to another. So, for people who already have push-access to the main repo it is not strictly necessary to fork in order to submit a pull request. Roman ___ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
RE: GHC 7.8 release?
We seem to be circling ever closer to consensus here! Yay! Indeed! Good :-) However, I’m not getting the bit about API changing vs non-API changing. Firstly I don’t know which APIs are intended. The GHC API is essentially GHC itself, so it changes daily. Maybe you mean the base package? Or what? I suspect you mean that a “non-API-changing” release absolutely guarantees to compile any package that compiled with the previous version. If so, that is a very strong constraint indeed. We do observe it for patch releases for GHC (e g 7.6.2 should compile anything that 7.6.1 compiles). But I think it would be difficult to guarantee for anything beyond a patch release. Every single commit (and the commit rate is many/day) would have to be evaluated against this criterion. And if it failed the criterion, it would have to go on a API-breaking HEAD. In effect we’d have two HEADs. I can’t see us sustaining this. And I don’t yet really see why it’s necessary. If you don’t want an API-breaking change, stick with the patch releases. So, we have a channel for non-API-breaking changes already: the patch releases. So that means we already have all three channels! ·Haskell Platform ·Patch-level releases ·New releases if that’s so, all we need is better signposting. And I’m all for that! Have I got this right? Simon From: Mark Lentczner [mailto:mark.lentcz...@gmail.com] Sent: 09 February 2013 17:48 To: Simon Marlow; Manuel M T Chakravarty; Johan Tibell; Simon Peyton-Jones; Mark Lentczner; andreas.voel...@gmail.com; Carter Schonwald; kosti...@gmail.com; Edsko de Vries; ghc-d...@haskell.org; glasgow-haskell-users Subject: Re: GHC 7.8 release? We seem to be circling ever closer to consensus here! Yay! I think the distinction of non-API breaking and API breaking release is very important. Refining SPJ's trifecta: Haskell Platform comes out twice a year. It is based on very stable version of GHC, and intention is that people can just assume things on Hackage work with it. These are named for the year and sequence of the release: 2013.2, 2013.2.1, 2013.4,... Non-API breaking releases can come out as often as desired. However, the version that is current as of mid-Feb. and mid-Aug. will be the ones considered for HP inclusion. By non-API breaking we mean the whole API surface including all the libraries bundled with GHC, as well as the operation of ghc, cabal, ghc-pkg, etc. Additions of features that must be explicitly enabled are okay. Additions of new APIs into existing modules are discouraged: Much code often imports base modules wholesale, and name clashes could easily result. These should never bump the major revision number: 7.4.1, 7.4.2... API breaking releases happen by being released into a separate channel when ready for library owners to look at them. This channel should probably go through several stages: Ready for core package owners to work with, then HP package owners, then all package owners. I'd imagine this is a several month process. At the end of which, the release can go into the main channel. Such a merge shouldn't happen more than once a year... I think even once every two years is fine (!) To avoid confusion, I'd suggest that while in the separate channel, these release be named with odd number: 7.9, 7.11,..., and when moved to the main channel renamed to even: 7.10, 7.12... This idea of three channels needs to be much more clearly communicated. The warning on the download page is a failure: Googling ghc takes you to the home page of GHC which immediately trumpets the Lastest News of a release of GHC 7.6.2. Once a user has read that and decided to download, then STOP! box is a) going to be skipped as they scan for the download link, and b) if read and followed, causes the WTF? Why is HP so back rev? So we need to change the front page so that the three channels are clearly communicated and targeted at the right users. - Mark (BTW: The first few links on the GHC web site are out of date: The second nav link is to a survey that is 7 years old. The License page is 8 years out of date. The FAQ is over a year old.) On Sat, Feb 9, 2013 at 8:24 AM, Ian Lynagh i...@well-typed.commailto:i...@well-typed.com wrote: On Sat, Feb 09, 2013 at 12:06:12PM +, Simon Marlow wrote: As a straw man, let's suppose we want to do annual API releases in September, with intermediate non-API releases in February. That's a non-API release 5 months after the API release. 6.10.2 was 5 months after 6.10.1 (.3 was 1 month later, .4 a further 2) 6.12.2 was 4 months after 6.12.1 (.3 was 2 months later) 7.0.2 was 3.5 months after 7.0.1 (.3 was 1 month later, .4 a further 3) 7.2.2 was 3 months after 7.2.1 7.4.2 was 4 months after 7.4.1 7.6.2 was 4.5 months after 7.6.2 so if we do non-API releases, then perhaps it would make sense to stop doing minor releases (unless a release turns out to just be broken). Thanks Ian
RE: GHC 7.8 release?
, even a point release (7.6.2 vs. 7.6.1) of ghc tends to be moderately violent with respect to the Platform. Ideally, such a point release should not be difficult to slot in because it should be compatible modulo bug fixes, but with ghc's release strategy nobody has any confidence in it being that simple. Well our clear intention for point releases (7.6.1 to 7.6.1) is that they should break nothing. I am concerned that in your experience point releases are “moderately violent”. We go to some pains to make sure that we don’t break anything.If we don’t succeed on this point-release policy, please do tell us when the release candidate comes out. If we don’t know we are causing pain, we can’t stop inflicting it :-) (Major releases are another matter. There, things are likely to break.) Simon From: Brandon Allbery [mailto:allber...@gmail.com] Sent: 09 February 2013 13:41 To: Simon Peyton-Jones Cc: Carter Schonwald; Manuel Chakravarty; parallel-haskell; Mark Lentczner; GHC Users List; ghc-d...@haskell.org; Edsko de Vries Subject: Re: GHC 7.8 release? On Sat, Feb 9, 2013 at 6:27 AM, Simon Peyton-Jones simo...@microsoft.commailto:simo...@microsoft.com wrote: In short, I think we already have the situation that you desire. Perhaps we just need to market it better? Or am I mistaken? Except the current question is about how ghc releases interact with the Platform; this thread was set off by a question about getting 7.6.2 into the next Platform And the main issue there is that ghc releases tend to break things and need a lot of testing in general to make it into the Platform; while this would be expected anyway, even a point release (7.6.2 vs. 7.6.1) of ghc tends to be moderately violent with respect to the Platform. Ideally, such a point release should not be difficult to slot in because it should be compatible modulo bug fixes, but with ghc's release strategy nobody has any confidence in it being that simple. -- brandon s allbery kf8nh sine nomine associates allber...@gmail.commailto:allber...@gmail.com ballb...@sinenomine.netmailto:ballb...@sinenomine.net unix, openafs, kerberos, infrastructure, xmonadhttp://sinenomine.net ___ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
Re: GHC 7.8 release?
On 10/02/13 15:36, Simon Peyton-Jones wrote: We seem to be circling ever closer to consensus here! Yay! Indeed! Good :-) However, I’m not getting the bit about API changing vs non-API changing. Firstly I don’t know which APIs are intended. The GHC API is essentially GHC itself, so it changes daily. Maybe you mean the base package? Or what? I suspect you mean that a “non-API-changing” release absolutely guarantees to compile any package that compiled with the previous version. If so, that is a very strong constraint indeed. We do observe it for patch releases for GHC (e g 7.6.2 should compile anything that 7.6.1 compiles). But I think it would be difficult to guarantee for anything beyond a patch release. Every single commit (and the commit rate is many/day) would have to be evaluated against this criterion. And if it failed the criterion, it would have to go on a API-breaking HEAD. In effect we’d have two HEADs. I can’t see us sustaining this. And I don’t yet really see why it’s necessary. If you don’t want an API-breaking change, stick with the patch releases. So, we have a channel for non-API-breaking changes already: the patch releases. So that means we already have all three channels! Mark is asking for major GHC releases every year at the most, preferably less frequently. That means major GHC releases in the sense that we do them now, where libraries change, and a wave of package updates are required to get everything working. Johan, Manuel and Carter are saying that they want releases that add features but don't break code, i.e. a non-API-breaking release, as a way to get the new bits into the hands of the punters sooner. This is something that we don't do right now, and it would entail a change to our workflow and release schedule. It doesn't mean no API changes at all - we would have to allow APIs to be extended, because many feature additions come with new primops, or new supporting code in the ghc-prim or base packages. The package version policy states precisely what it means to extend an API (http://www.haskell.org/haskellwiki/Package_versioning_policy) and most third-party packages will still work so long as we only bump the minor versions of the packages that come with GHC. The GHC package itself would have to be exempt, because it contains every module in GHC, and hence would be impossible to keep stable if we are modifying the compiler to add new features. Of course it's not practical to maintain an extra branch of GHC for non-API-breaking development - two branches is already plenty. So there would need to be an API-freeze for a while between the major release and the non-API-breaking release, during which time people developing API changes would need to work on branches. Is it workable? I'm not sure, but I think it's worth a try. I wouldn't want to see this replace the patchlevel bugfix releases that we already do, and as Ian points out, there isn't a lot of room in the release schedule for more releases, unless we stretch out the timescales, doing major releases less frequently. Cheers, Simon ·Haskell Platform ·Patch-level releases ·New releases if that’s so, all we need is better signposting. And I’m all for that! Have I got this right? Simon *From:*Mark Lentczner [mailto:mark.lentcz...@gmail.com] *Sent:* 09 February 2013 17:48 *To:* Simon Marlow; Manuel M T Chakravarty; Johan Tibell; Simon Peyton-Jones; Mark Lentczner; andreas.voel...@gmail.com; Carter Schonwald; kosti...@gmail.com; Edsko de Vries; ghc-d...@haskell.org; glasgow-haskell-users *Subject:* Re: GHC 7.8 release? We seem to be circling ever closer to consensus here! Yay! I think the distinction of non-API breaking and API breaking release is very important. Refining SPJ's trifecta: *Haskell Platform* comes out twice a year. It is based on very stable version of GHC, and intention is that people can just assume things on Hackage work with it. These are named for the year and sequence of the release: 2013.2, 2013.2.1, 2013.4,... *Non-API breaking releases* can come out as often as desired. However, the version that is current as of mid-Feb. and mid-Aug. will be the ones considered for HP inclusion. By non-API breaking we mean the whole API surface including all the libraries bundled with GHC, as well as the operation of ghc, cabal, ghc-pkg, etc. Additions of features that must be explicitly enabled are okay. Additions of new APIs into existing modules are discouraged: Much code often imports base modules wholesale, and name clashes could easily result. These should never bump the major revision number: 7.4.1, 7.4.2... *API breaking releases* happen by being released into a separate channel when ready for library owners to look at them. This channel should probably go through several stages: Ready for core package owners to work with, then HP package owners, then all
RE: GHC 7.8 release?
What I am still missing is this: | Mark is asking for major GHC releases every year at the most, preferably | less frequently. That means major GHC releases in the sense that we do | them now, where libraries change, and a wave of package updates are | required to get everything working. What causes the wave of package updates? Just because GHC 7.8 (say) comes out, no package author need lift a finger. The Haskell Platform sets the pace for package updates. When the Haskell Platform comes out, now THAT is indeed a trigger for a wave of updates. Authors of packages in HP are forced to act; authors of other packages want their packages to work with the next HP. But there is no reason why package authors should respond to GHC releases, provided we signpost it accurately. You may ask what use is a GHC release that doesn't cause a wave of updates? And hence that doesn't work with at least some libraries. Well, it's a very useful forcing function to get new features actually out and tested. Of course we could just not do that, and say build from source, but a release brings a welcome discipline. But under this story, release or not-release would be a Little Deal, not a Big Deal. The benefits are modest; the costs are modest. In short, I'm continuing to propose that we stick to the current story, but signpost it better. If it ain't broke, don't fix it --- or at least fix only the bits that are broken, which is the signposting. Simon | | Johan, Manuel and Carter are saying that they want releases that add | features but don't break code, i.e. a non-API-breaking release, as a way | to get the new bits into the hands of the punters sooner. This is | something that we don't do right now, and it would entail a change to | our workflow and release schedule. | | It doesn't mean no API changes at all - we would have to allow APIs to | be extended, because many feature additions come with new primops, or | new supporting code in the ghc-prim or base packages. The package | version policy states precisely what it means to extend an API | (http://www.haskell.org/haskellwiki/Package_versioning_policy) and most | third-party packages will still work so long as we only bump the minor | versions of the packages that come with GHC. | | The GHC package itself would have to be exempt, because it contains | every module in GHC, and hence would be impossible to keep stable if we | are modifying the compiler to add new features. | | Of course it's not practical to maintain an extra branch of GHC for | non-API-breaking development - two branches is already plenty. So there | would need to be an API-freeze for a while between the major release and | the non-API-breaking release, during which time people developing API | changes would need to work on branches. | | Is it workable? I'm not sure, but I think it's worth a try. I wouldn't | want to see this replace the patchlevel bugfix releases that we already | do, and as Ian points out, there isn't a lot of room in the release | schedule for more releases, unless we stretch out the timescales, doing | major releases less frequently. | | Cheers, | Simon | | | ·Haskell Platform | | ·Patch-level releases | | ·New releases | | | if that’s so, all we need is better signposting. And I’m all for that! | | Have I got this right? | | | Simon | | *From:*Mark Lentczner [mailto:mark.lentcz...@gmail.com] | *Sent:* 09 February 2013 17:48 | *To:* Simon Marlow; Manuel M T Chakravarty; Johan Tibell; Simon | Peyton-Jones; Mark Lentczner; andreas.voel...@gmail.com; Carter | Schonwald; kosti...@gmail.com; Edsko de Vries; ghc-d...@haskell.org; | glasgow-haskell-users | *Subject:* Re: GHC 7.8 release? | | We seem to be circling ever closer to consensus here! Yay! | | I think the distinction of non-API breaking and API breaking release is | very important. Refining SPJ's trifecta: | | *Haskell Platform* comes out twice a year. It is based on very | stable version of GHC, and intention is that people can just assume | things on Hackage work with it. These are named for the year and | sequence of the release: 2013.2, 2013.2.1, 2013.4,... | | *Non-API breaking releases* can come out as often as desired. | However, the version that is current as of mid-Feb. and mid-Aug. | will be the ones considered for HP inclusion. By non-API breaking we | mean the whole API surface including all the libraries bundled with | GHC, as well as the operation of ghc, cabal, ghc-pkg, etc. Additions | of features that must be explicitly enabled are okay. Additions of | new APIs into existing modules are discouraged: Much code often | imports base modules wholesale, and name clashes could easily | result. These should never bump the major revision number: 7.4.1, | 7.4.2... | | *API breaking
Re: GHC 7.8 release?
On Sun, Feb 10, 2013 at 09:02:18PM +, Simon Peyton-Jones wrote: You may ask what use is a GHC release that doesn't cause a wave of updates? And hence that doesn't work with at least some libraries. Well, it's a very useful forcing function to get new features actually out and tested. But the way you test new features is to write programs that use them, and programs depend on libraries. Thanks Ian ___ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
Re: GHC 7.8 release?
On 10 February 2013 13:02, Simon Peyton-Jones simo...@microsoft.com wrote: What I am still missing is this: | Mark is asking for major GHC releases every year at the most, preferably | less frequently. That means major GHC releases in the sense that we do | them now, where libraries change, and a wave of package updates are | required to get everything working. What causes the wave of package updates? Just because GHC 7.8 (say) comes out, no package author need lift a finger. The Haskell Platform sets the pace for package updates. When the Haskell Platform comes out, now THAT is indeed a trigger for a wave of updates. Authors of packages in HP are forced to act; authors of other packages want their packages to work with the next HP. But there is no reason why package authors should respond to GHC releases, provided we signpost it accurately. You may ask what use is a GHC release that doesn't cause a wave of updates? And hence that doesn't work with at least some libraries. Well, it's a very useful forcing function to get new features actually out and tested. Of course we could just not do that, and say build from source, but a release brings a welcome discipline. But under this story, release or not-release would be a Little Deal, not a Big Deal. The benefits are modest; the costs are modest. In short, I'm continuing to propose that we stick to the current story, but signpost it better. If it ain't broke, don't fix it --- or at least fix only the bits that are broken, which is the signposting. My understanding of the proposed changes (which I'm also supportive of) is to separate GHC improvements that break existing libraries (or perhaps even simply add language level features), and those that are improvements under-the-hood (e.g., bug fixes, performance improvements). So rather than 7.8 be a huge single release containing new type level features, SIMD, the new code-generator. There would be two releases, one containing just say the new-code-generator, improvements to the IO manager, potentially also DPH... another release would containing new language level improvements. So then HP can benefit from improvements to the existing language and API without having to also pull in breaking (or just extending) changes... It's the issue of a research compiler Vs. and industrial compiler and managing that more explicitly in the release model. Cheers, David Simon | | Johan, Manuel and Carter are saying that they want releases that add | features but don't break code, i.e. a non-API-breaking release, as a way | to get the new bits into the hands of the punters sooner. This is | something that we don't do right now, and it would entail a change to | our workflow and release schedule. | | It doesn't mean no API changes at all - we would have to allow APIs to | be extended, because many feature additions come with new primops, or | new supporting code in the ghc-prim or base packages. The package | version policy states precisely what it means to extend an API | (http://www.haskell.org/haskellwiki/Package_versioning_policy) and most | third-party packages will still work so long as we only bump the minor | versions of the packages that come with GHC. | | The GHC package itself would have to be exempt, because it contains | every module in GHC, and hence would be impossible to keep stable if we | are modifying the compiler to add new features. | | Of course it's not practical to maintain an extra branch of GHC for | non-API-breaking development - two branches is already plenty. So there | would need to be an API-freeze for a while between the major release and | the non-API-breaking release, during which time people developing API | changes would need to work on branches. | | Is it workable? I'm not sure, but I think it's worth a try. I wouldn't | want to see this replace the patchlevel bugfix releases that we already | do, and as Ian points out, there isn't a lot of room in the release | schedule for more releases, unless we stretch out the timescales, doing | major releases less frequently. | | Cheers, | Simon | | | ·Haskell Platform | | ·Patch-level releases | | ·New releases | | | if that’s so, all we need is better signposting. And I’m all for that! | | Have I got this right? | | | Simon | | *From:*Mark Lentczner [mailto:mark.lentcz...@gmail.com] | *Sent:* 09 February 2013 17:48 | *To:* Simon Marlow; Manuel M T Chakravarty; Johan Tibell; Simon | Peyton-Jones; Mark Lentczner; andreas.voel...@gmail.com; Carter | Schonwald; kosti...@gmail.com; Edsko de Vries; ghc-d...@haskell.org; | glasgow-haskell-users | *Subject:* Re: GHC 7.8 release? | | We seem to be circling ever closer to consensus here! Yay! | | I think the distinction of non-API breaking and API breaking release is | very important. Refining SPJ's
RE: GHC 7.8 release?
| You may ask what use is a GHC release that doesn't cause a wave of updates? | And hence that doesn't work with at least some libraries. Well, it's a very useful | forcing function to get new features actually out and tested. | | But the way you test new features is to write programs that use them, | and programs depend on libraries. That is of course ideal, but the ideal carries costs. A half way house is a release whose library support will be patchy. Not such good testing, but much lower costs. But still (I think) a lot more testing than compile HEAD gives us. Simon ___ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
Re: GHC 7.8 release?
On Sun, Feb 10, 2013 at 09:30:23PM +, Simon Peyton-Jones wrote: | You may ask what use is a GHC release that doesn't cause a wave of updates? | And hence that doesn't work with at least some libraries. Well, it's a very useful | forcing function to get new features actually out and tested. | | But the way you test new features is to write programs that use them, | and programs depend on libraries. That is of course ideal, but the ideal carries costs. A half way house is a release whose library support will be patchy. But that's not what happens. GHC 7.8 is released. Someone installs it in order to try to use TypeHoles when developing their program. But their program depends on text, so they send Bryan a mail saying that text doesn't build with 7.8. And so the wave of updates begins. Thanks Ian ___ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
Re: GHC 7.8 release?
On 10/02/2013 21:43, Ian Lynagh wrote: On Sun, Feb 10, 2013 at 09:30:23PM +, Simon Peyton-Jones wrote: | You may ask what use is a GHC release that doesn't cause a wave of updates? | And hence that doesn't work with at least some libraries. Well, it's a very useful | forcing function to get new features actually out and tested. | | But the way you test new features is to write programs that use them, | and programs depend on libraries. That is of course ideal, but the ideal carries costs. A half way house is a release whose library support will be patchy. But that's not what happens. GHC 7.8 is released. Someone installs it in order to try to use TypeHoles when developing their program. But their program depends on text, so they send Bryan a mail saying that text doesn't build with 7.8. And so the wave of updates begins. As the maintainer of a low-level package (HTTP), I certainly see this kind of pressure starting even before a GHC release - e.g. https://github.com/haskell/HTTP/issues/36 As one of the maintainers of a high-level tool (darcs) that aims to always build against the current HP, I generate this kind of pressure myself: once GHC is released, I expect it to be in the HP within 3-6 months, so I need to get started quickly. I can't even check darcs itself until the dependencies work. I don't think there are any easy answers :-/ Ganesh ___ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
Re: GHC 7.8 release?
Yes, exactly this. A release where the versions of base, and all other baked in libraries are only minor version bumps and where breaking changes are localized to relatively experimental language features / extensions and GHC specific APIs would ideal. Eg: I'm OK having to patch ghc-mod so it works with a new intermediate GHC release. (Esp since it uses GHC internal apis) The new scheduler improvements, the recent doh work , the great SIMD work / code generator improvments, the type level nats, ordered type families, the overloaded list syntax, All of these extensions and associated API augmentations should not break stable libraries, at least on minor version bumps, cause 1) maybe experimental new APIs can be included in minor releases as separate explicitly experimental modules (this gives a way of including new functionality in a minor release) 2) generally type checking / inference on stable code that doesn't enable new features stays the same. I'm probably overlooking some pieces or. Details, and I'm largely restating what Johan and Manuel have communicated. -Carter On Feb 10, 2013 4:43 PM, Ian Lynagh i...@well-typed.com wrote: On Sun, Feb 10, 2013 at 09:30:23PM +, Simon Peyton-Jones wrote: | You may ask what use is a GHC release that doesn't cause a wave of updates? | And hence that doesn't work with at least some libraries. Well, it's a very useful | forcing function to get new features actually out and tested. | | But the way you test new features is to write programs that use them, | and programs depend on libraries. That is of course ideal, but the ideal carries costs. A half way house is a release whose library support will be patchy. But that's not what happens. GHC 7.8 is released. Someone installs it in order to try to use TypeHoles when developing their program. But their program depends on text, so they send Bryan a mail saying that text doesn't build with 7.8. And so the wave of updates begins. Thanks Ian ___ ghc-devs mailing list ghc-d...@haskell.org http://www.haskell.org/mailman/listinfo/ghc-devs ___ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
Re: GHC 7.8 release?
On Sun, Feb 10, 2013 at 3:16 PM, Ian Lynagh i...@well-typed.com wrote: On Sun, Feb 10, 2013 at 09:02:18PM +, Simon Peyton-Jones wrote: You may ask what use is a GHC release that doesn't cause a wave of updates? And hence that doesn't work with at least some libraries. Well, it's a very useful forcing function to get new features actually out and tested. But the way you test new features is to write programs that use them, and programs depend on libraries. Thanks Ian Releasing GHC early and often (possibly with API breakage) isn't really the problem. The real problem is how to coordinate with library authors (e.g. Haskell Platform), etc. I suspect GHC should continue to offer a platform for research and experiments. That is much harder if you curtail the ability to release GHC early and often. -- Gaby ___ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
Re: GHC 7.8 release?
Well said. Having a more aggressive release cycle is another interesting perspective. On Feb 10, 2013 6:21 PM, Gabriel Dos Reis g...@integrable-solutions.net wrote: On Sun, Feb 10, 2013 at 3:16 PM, Ian Lynagh i...@well-typed.com wrote: On Sun, Feb 10, 2013 at 09:02:18PM +, Simon Peyton-Jones wrote: You may ask what use is a GHC release that doesn't cause a wave of updates? And hence that doesn't work with at least some libraries. Well, it's a very useful forcing function to get new features actually out and tested. But the way you test new features is to write programs that use them, and programs depend on libraries. Thanks Ian Releasing GHC early and often (possibly with API breakage) isn't really the problem. The real problem is how to coordinate with library authors (e.g. Haskell Platform), etc. I suspect GHC should continue to offer a platform for research and experiments. That is much harder if you curtail the ability to release GHC early and often. -- Gaby ___ ghc-devs mailing list ghc-d...@haskell.org http://www.haskell.org/mailman/listinfo/ghc-devs ___ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
Re: GHC 7.8 release?
On Sun, Feb 10, 2013 at 4:02 PM, Simon Peyton-Jones simo...@microsoft.comwrote: What causes the wave of package updates? Just because GHC 7.8 (say) comes out, no package author need lift a finger. The Haskell Platform sets the pace for package updates. When the Haskell Platform comes out, now THAT is indeed a trigger for a wave of updates. Authors of packages in HP are forced to act; authors of other packages want their packages to work with the next HP. (a) There are packages which tend to track GHC's latest version instead of the HP (yesod used to do this, which was a source of much pain). (b) There are linux distributions which always track the latest everything, often in a rolling-release fashion (notably Arch). They are actively hostile to the Platform, and a source of even greater pain. Many package authors update because Arch users demand it and openly insult anyone who points them to the Platform or any policy which suggests that anything other then the absolutely latest version is acceptable. You *might* be able to control expectations with respect to (a); (b) is not subject to any variety of reason. It will produce as much pressure as it has users, plus multiply that pressure by the number of package authors who are also users. -- brandon s allbery kf8nh sine nomine associates allber...@gmail.com ballb...@sinenomine.net unix, openafs, kerberos, infrastructure, xmonadhttp://sinenomine.net ___ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
Re: GHC 7.8 release?
While I'm notionally in favor of decoupling API-breaking changes from non-API breaking changes, there are two major difficulties: GHC.Prim and Template Haskell. Should a non-API-breaking change mean that GHC.Prim is immutable? If so, this greatly restricts GHC's development. If not, it means that a large chunk of hackage will become unbuildable due to deps on vector and primitive. With Template Haskell the situation is largely similar, although the deps are different. What I would like to see are more patch-level bugfix releases. I suspect the reason we don't have more is that making a release is a lot of work. So, Ian, what needs to happen to make more frequent patch releases feasible? On Mon, Feb 11, 2013 at 7:42 AM, Carter Schonwald carter.schonw...@gmail.com wrote: Well said. Having a more aggressive release cycle is another interesting perspective. On Feb 10, 2013 6:21 PM, Gabriel Dos Reis g...@integrable-solutions.net wrote: On Sun, Feb 10, 2013 at 3:16 PM, Ian Lynagh i...@well-typed.com wrote: On Sun, Feb 10, 2013 at 09:02:18PM +, Simon Peyton-Jones wrote: You may ask what use is a GHC release that doesn't cause a wave of updates? And hence that doesn't work with at least some libraries. Well, it's a very useful forcing function to get new features actually out and tested. But the way you test new features is to write programs that use them, and programs depend on libraries. Thanks Ian Releasing GHC early and often (possibly with API breakage) isn't really the problem. The real problem is how to coordinate with library authors (e.g. Haskell Platform), etc. I suspect GHC should continue to offer a platform for research and experiments. That is much harder if you curtail the ability to release GHC early and often. -- Gaby ___ ghc-devs mailing list ghc-d...@haskell.org http://www.haskell.org/mailman/listinfo/ghc-devs ___ ghc-devs mailing list ghc-d...@haskell.org http://www.haskell.org/mailman/listinfo/ghc-devs ___ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
