November 2015 - ghc-devs

RE: D1428: Rework treatment of wildcards
by Simon Peyton Jones 26 Nov '15

26 Nov '15

Ben So that you know, the state of play is: * wip/spj-wildcard-refactor is fully up to speed with HEAD * It validates except for perf/compiler/T3064 (8% loss) * It does need a decent commit message I'd really like this in 8.0: - It's a big patch, so not having it will lead to lots of tiresome cross-branch porting - It does fix things in the wildcard story Of these the former is the more important. The only think holding me up is that I really don't understand the perf regression. It seems to be in the simplifier, which I have not touched! Working on it. But in the worst case I can commit and open a ticket for the perf regression Simon | -----Original Message----- | From: noreply(a)phabricator.haskell.org | [mailto:noreply@phabricator.haskell.org] | Sent: 26 November 2015 14:40 | To: Simon Peyton Jones <simonpj(a)microsoft.com> | Subject: [Differential] [Requested Changes To] D1428: Rework treatment | of wildcards | | bgamari requested changes to this revision. | bgamari added a comment. | This revision now requires changes to proceed. | | Requesting changes to bump this out of the review queue. | | | REPOSITORY | rGHC Glasgow Haskell Compiler | | REVISION DETAIL | https://phabricator.haskell.org/D1428 | | EMAIL PREFERENCES | https://phabricator.haskell.org/settings/panel/emailpreferences/ | | To: austin, hvr, goldfire, simonpj, bgamari | Cc: jstolarek, alanz, goldfire, thomie, mpickering, simonpj

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Re: [GHC] #11028: Refactor ConDecl
by Alan & Kim Zimmerman 25 Nov '15

25 Nov '15

As I wrote that I came to the same conclusion, but decided to leave the rest in case. On Thu, Nov 26, 2015 at 12:25 AM, GHC <ghc-devs(a)haskell.org> wrote: > #11028: Refactor ConDecl > -------------------------------------+------------------------------------- > Reporter: simonpj | Owner: alanz > Type: bug | Status: new > Priority: normal | Milestone: > Component: Compiler | Version: 7.10.2 > Resolution: | Keywords: > Operating System: Unknown/Multiple | Architecture: > | Unknown/Multiple > Type of failure: None/Unknown | Test Case: > Blocked By: | Blocking: > Related Tickets: | Differential Rev(s): > Wiki Page: | > -------------------------------------+------------------------------------- > > Comment (by simonpj): > > > Alternatively, everything except the `rnLHsType` in `rnConResult` can > move to the type checking. > > That sounds exactly right. `Note [Sorting out the result type]` in > `RdrHsSyn` seems entirely redundant with the new `ConDeclGADT` form. > > -- > Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11028#comment:25> > GHC <http://www.haskell.org/ghc/> > The Glasgow Haskell Compiler >

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Re: [GHC] #11028: Refactor ConDecl
by Alan & Kim Zimmerman 25 Nov '15

25 Nov '15

I just pushed to wip/T11028 It is very much a work in progress, working through to sort out the compiler errors, in the simplest way at the moment. On Wed, Nov 25, 2015 at 3:06 PM, GHC <ghc-devs(a)haskell.org> wrote: > #11028: Refactor ConDecl > -------------------------------------+------------------------------------- > Reporter: simonpj | Owner: alanz > Type: bug | Status: new > Priority: normal | Milestone: > Component: Compiler | Version: 7.10.2 > Resolution: | Keywords: > Operating System: Unknown/Multiple | Architecture: > | Unknown/Multiple > Type of failure: None/Unknown | Test Case: > Blocked By: | Blocking: > Related Tickets: | Differential Rev(s): > Wiki Page: | > -------------------------------------+------------------------------------- > > Comment (by simonpj): > > Yes, because of the possibility of `HsRecTy`, you can't use `tcHsSigType`. > So something like what you propose looks good. > > Ca you make a branch and push what you have so that I can see? > > -- > Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11028#comment:19> > GHC <http://www.haskell.org/ghc/> > The Glasgow Haskell Compiler >

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Monad fail errors
by Simon Peyton Jones 24 Nov '15

24 Nov '15

Herbert In tests/monadfail/MonadFailErrors.stderr I see MonadFailErrors.hs:59:5: error: No instance for (MonadFail Identity) arising from a do statement with the failable pattern ‘Newtype x’ In a stmt of a 'do' block: Newtype x <- undefined In the expression: do { Newtype x <- undefined; undefined } In an equation for ‘newtypeMatch’: newtypeMatch = do { Newtype x <- undefined; undefined } MonadFailErrors.hs:67:5: error: No instance for (MonadFail Identity) arising from a do statement with the failable pattern ‘Data x’ In a stmt of a 'do' block: Data x <- undefined In the expression: do { Data x <- undefined; undefined } In an equation for ‘singleConMatch’: singleConMatch = do { Data x <- undefined; undefined } But ‘Newtype’ and ‘Data’ are single constructor types and hence cannot fail. So why are these errors happening? I’m tiding up your implementation (deleting code!) and accidentally fixed this. So I wanted to check that it is indeed wrong as-is. Simon

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RE: [GHC] #11019: ApiAnnotations: Make all RdrName occurences Located
by Simon Peyton Jones 23 Nov '15

23 Nov '15

The commit is a one-line change to IEThingAll, which says: -- See Note [Located RdrNames] in HsExpr But HsExpr does not contain such a Note. Did you omit something? Simon From: Alan & Kim Zimmerman [mailto:alan.zimm@gmail.com] Sent: 23 November 2015 13:40 To: Simon Peyton Jones <simonpj(a)microsoft.com> Subject: Re: [GHC] #11019: ApiAnnotations: Make all RdrName occurences Located Done, see https://phabricator.haskell.org/rGHC7c9a04d6eda5495f150a1140e6d26fc64e319b7e On Mon, Nov 23, 2015 at 12:13 PM, Simon Peyton Jones <simonpj(a)microsoft.com<mailto:simonpj@microsoft.com>> wrote: Alan | ApiAnnotations: Make all RdrName occurences Located There is a principle here: that every RdrName occurrence is located. Is this principle articulated in a Note anywhere? I wish it was! (Including an explanation of why.) Otherwise you risk someone removing the change in a few years time. When I built HsSyn originally I reasoned that data HsExpr = ...| HsVar RdrName was better than data HsExpr = ... | HsVar (Located RdrName0 because the location on the RdrName is identical to that on the LHsExpr, so it's redundant. But you think it is non-redundant. I'm sure you are right (although I don't know why), but it would be a real help to document the invariant and the reasoning in the code somewhere. Are there any other principles that the code embodies? Thanks Simon | -----Original Message----- | From: ghc-tickets [mailto:ghc-tickets-bounces@haskell.org<mailto:ghc-tickets-bounces@haskell.org>] On Behalf | Of GHC | Sent: 22 November 2015 23:11 | Cc: ghc-tickets(a)haskell.org<mailto:ghc-tickets@haskell.org> | Subject: Re: [GHC] #11019: ApiAnnotations: Make all RdrName occurences | Located | | #11019: ApiAnnotations: Make all RdrName occurences Located | -------------------------------------+-------------------------------- | -- | -------------------------------------+--- | Reporter: alanz | Owner: alanz | Type: bug | Status: new | Priority: normal | Milestone: 8.0.1 | Component: Compiler | Version: 7.10.2 | Resolution: | Keywords: | | ApiAnnotations | Operating System: Unknown/Multiple | Architecture: | | Unknown/Multiple | Type of failure: None/Unknown | Test Case: | Blocked By: | Blocking: | Related Tickets: | Differential Rev(s): | Phab:1512 | Wiki Page: | | -------------------------------------+-------------------------------- | -- | -------------------------------------+--- | | Comment (by Ben Gamari <ben@…>): | | In [changeset:"3df9563e590bbfbfe1bc9171a0e8fc93ceef690d/ghc" | 3df9563e/ghc]: | {{{ | #!CommitTicketReference repository="ghc" | revision="3df9563e590bbfbfe1bc9171a0e8fc93ceef690d" | ApiAnnotations: Make all RdrName occurences Located | | At the moment the API Annotations can only be used on the | ParsedSource, as there are changes made to the RenamedSource that | prevent it from being used to round trip source code. | | It is possible to build a map from every Located Name in the | RenamedSource from its location to the Name, which can then be used | when resolved names are required when changing the ParsedSource. | | However, there are instances where the identifier is not located, | specifically | | (GHC.VarPat name) | (GHC.HsVar name) | (GHC.UserTyVar name) | (GHC.HsTyVar name) | | Replace each of the name types above with (Located name) | | Updates the haddock submodule. | | Test Plan: ./validate | | Reviewers: austin, goldfire, bgamari | | Reviewed By: bgamari | | Subscribers: goldfire, thomie, mpickering | | Differential Revision: https://phabricator.haskell.org/D1512 | | GHC Trac Issues: #11019 | }}} | | -- | Ticket URL: | <https://na01.safelinks.protection.outlook.com/?url=http%3a%2f%2fghc.h | askell.org<https://na01.safelinks.protection.outlook.com/?url=http%3a%2f%2faskell.org&…>%2ftrac%2fghc%2fticket%2f11019%23comment%3a5&data=01%7c01%7c | simonpj%40064d.mgd.microsoft.com<https://na01.safelinks.protection.outlook.com/?url=http%3a%2f%2f40064d.mgd.…>%7cd486e47f742f47e34e7308d2f39230b0%7c | 72f988bf86f141af91ab2d7cd011db47%7c1&sdata=AmQZ%2boKbdHXQ4cuPjYOVePqF7 | ivXocZyqHXbcyBj3GY%3d> | GHC | <https://na01.safelinks.protection.outlook.com/?url=http%3a%2f%2fwww.h | askell.org<https://na01.safelinks.protection.outlook.com/?url=http%3a%2f%2faskell.org&…>%2fghc%2f&data=01%7c01%7csimonpj%40064d.mgd.microsoft.com<https://na01.safelinks.protection.outlook.com/?url=http%3a%2f%2f40064d.mgd.…>%7c | d486e47f742f47e34e7308d2f39230b0%7c72f988bf86f141af91ab2d7cd011db47%7c | 1&sdata=Ca9k88QpvsPGDgrkQCANdKLAPCnAKwoZdHzbIhBgnIU%3d> | The Glasgow Haskell Compiler | _______________________________________________ | ghc-tickets mailing list | ghc-tickets(a)haskell.org<mailto:ghc-tickets@haskell.org> | https://na01.safelinks.protection.outlook.com/?url=http%3a%2f%2fmail.h | askell.org<https://na01.safelinks.protection.outlook.com/?url=http%3a%2f%2faskell.org&…>%2fcgi-bin%2fmailman%2flistinfo%2fghc- | tickets%0a&data=01%7c01%7csimonpj%40064d.mgd.microsoft.com<https://na01.safelinks.protection.outlook.com/?url=http%3a%2f%2f40064d.mgd.…>%7cd486e47f7 | 42f47e34e7308d2f39230b0%7c72f988bf86f141af91ab2d7cd011db47%7c1&sdata=Q | aS%2fcmZrioGbpGHXUFNcdCmhyFt6mnV4DH4ucOsO7eo%3d

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RE: [GHC] #11019: ApiAnnotations: Make all RdrName occurences Located
by Simon Peyton Jones 23 Nov '15

23 Nov '15

Alan | ApiAnnotations: Make all RdrName occurences Located There is a principle here: that every RdrName occurrence is located. Is this principle articulated in a Note anywhere? I wish it was! (Including an explanation of why.) Otherwise you risk someone removing the change in a few years time. When I built HsSyn originally I reasoned that data HsExpr = ...| HsVar RdrName was better than data HsExpr = ... | HsVar (Located RdrName0 because the location on the RdrName is identical to that on the LHsExpr, so it's redundant. But you think it is non-redundant. I'm sure you are right (although I don't know why), but it would be a real help to document the invariant and the reasoning in the code somewhere. Are there any other principles that the code embodies? Thanks Simon | -----Original Message----- | From: ghc-tickets [mailto:ghc-tickets-bounces@haskell.org] On Behalf | Of GHC | Sent: 22 November 2015 23:11 | Cc: ghc-tickets(a)haskell.org | Subject: Re: [GHC] #11019: ApiAnnotations: Make all RdrName occurences | Located | | #11019: ApiAnnotations: Make all RdrName occurences Located | -------------------------------------+-------------------------------- | -- | -------------------------------------+--- | Reporter: alanz | Owner: alanz | Type: bug | Status: new | Priority: normal | Milestone: 8.0.1 | Component: Compiler | Version: 7.10.2 | Resolution: | Keywords: | | ApiAnnotations | Operating System: Unknown/Multiple | Architecture: | | Unknown/Multiple | Type of failure: None/Unknown | Test Case: | Blocked By: | Blocking: | Related Tickets: | Differential Rev(s): | Phab:1512 | Wiki Page: | | -------------------------------------+-------------------------------- | -- | -------------------------------------+--- | | Comment (by Ben Gamari <ben@…>): | | In [changeset:"3df9563e590bbfbfe1bc9171a0e8fc93ceef690d/ghc" | 3df9563e/ghc]: | {{{ | #!CommitTicketReference repository="ghc" | revision="3df9563e590bbfbfe1bc9171a0e8fc93ceef690d" | ApiAnnotations: Make all RdrName occurences Located | | At the moment the API Annotations can only be used on the | ParsedSource, as there are changes made to the RenamedSource that | prevent it from being used to round trip source code. | | It is possible to build a map from every Located Name in the | RenamedSource from its location to the Name, which can then be used | when resolved names are required when changing the ParsedSource. | | However, there are instances where the identifier is not located, | specifically | | (GHC.VarPat name) | (GHC.HsVar name) | (GHC.UserTyVar name) | (GHC.HsTyVar name) | | Replace each of the name types above with (Located name) | | Updates the haddock submodule. | | Test Plan: ./validate | | Reviewers: austin, goldfire, bgamari | | Reviewed By: bgamari | | Subscribers: goldfire, thomie, mpickering | | Differential Revision: https://phabricator.haskell.org/D1512 | | GHC Trac Issues: #11019 | }}} | | -- | Ticket URL: | <https://na01.safelinks.protection.outlook.com/?url=http%3a%2f%2fghc.h | askell.org%2ftrac%2fghc%2fticket%2f11019%23comment%3a5&data=01%7c01%7c | simonpj%40064d.mgd.microsoft.com%7cd486e47f742f47e34e7308d2f39230b0%7c | 72f988bf86f141af91ab2d7cd011db47%7c1&sdata=AmQZ%2boKbdHXQ4cuPjYOVePqF7 | ivXocZyqHXbcyBj3GY%3d> | GHC | <https://na01.safelinks.protection.outlook.com/?url=http%3a%2f%2fwww.h | askell.org%2fghc%2f&data=01%7c01%7csimonpj%40064d.mgd.microsoft.com%7c | d486e47f742f47e34e7308d2f39230b0%7c72f988bf86f141af91ab2d7cd011db47%7c | 1&sdata=Ca9k88QpvsPGDgrkQCANdKLAPCnAKwoZdHzbIhBgnIU%3d> | The Glasgow Haskell Compiler | _______________________________________________ | ghc-tickets mailing list | ghc-tickets(a)haskell.org | https://na01.safelinks.protection.outlook.com/?url=http%3a%2f%2fmail.h | askell.org%2fcgi-bin%2fmailman%2flistinfo%2fghc- | tickets%0a&data=01%7c01%7csimonpj%40064d.mgd.microsoft.com%7cd486e47f7 | 42f47e34e7308d2f39230b0%7c72f988bf86f141af91ab2d7cd011db47%7c1&sdata=Q | aS%2fcmZrioGbpGHXUFNcdCmhyFt6mnV4DH4ucOsO7eo%3d

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On parsing Haskell and CPP
by Gershom B 22 Nov '15

22 Nov '15

We've had quite a bit of discussion lately on the difficulty in performing automated processing of Haskell files in the presence of CPP. It turns out that folks have tackled this sort of problem in the world of C, and done some interesting work. I recently ran across SuperC [1], part of the xtc [2] project. In the setting of C they have achieved some impressive results, including as I understand it, the ability to handle the entire Linux kernel across all CPP-recognized configurations. They note that this is a rather tedious to implement task, even once one has recognized the specification of how to do so. However, the paper is good at reviewing related work and simpler techniques as well, and perhaps among them there is a "good enough" set for the CPP used in common Haskell libraries? Cheers, Gershom [1] https://cs.nyu.edu/rgrimm/papers/pldi12.pdf [2] http://cs.nyu.edu/xtc/

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Re: mac platform problem with configure in 7.10.3 release candidate 3
by George Colpitts 22 Nov '15

22 Nov '15

On MacOS if your path is such that gcc is the gnu gcc rather than Apple's gcc then ./configure gives checking whether we are cross compiling... configure: error: in `/Users/gcolpitts/downloads/ghc-7.10.2.20151114': configure: error: cannot run C compiled programs. If you meant to cross compile, use `--host'. See `config.log' for more details I worked around this by doing export PATH=/usr/bin:$PATH before doing ./configure After that the install worked fine. Thanks On Wed, Nov 18, 2015 at 10:48 AM, Ben Gamari <ben(a)well-typed.com> wrote: > > Hello everyone, > > We are pleased to announce the third release candidate of GHC 7.10.3: > > https://downloads.haskell.org/~ghc/7.10.3-rc3/ > > There have been a few changes since -rc2, > > * The newly-introduced readelf configure check has been disabled on > non-ELF platforms > > * Some tracing output from the typechecker that was causing > some testsuites to fail was removed > > * A latent bug in call arity analysis (#11064) is fixed > > * A code generation bug (#10870) in the PowerPC NCG is fixed > > * A bug in the treatment of foreign calls during demand analysis > (#11076) which had affected GHCJS is fixed > > * A bug in the x86 NCG causing invalid assembly to be produced > when compiling with `-g` is fixed. > > At this moment you will find the source tarball, as well as, 64-bit > Windows, Mac OS X, 32- and 64-bit modern Linux (built on Debian 8) > binary distributions available at the above URL. As usual, you may need > to work around our content delivery network's update latency by adding > redundant forward-slashes to the URL. > > It has come to our attention that there still may be some issues with > long command lines on Windows with this release: While the toolchain > upgrade included in this release has the response file support necessary > to work around this limitation, the version of the Cabal library > shipped with this release does not. Unfortunately, the fix [1], which > affects Cabal's haddock integration, has not yet shipped in a Cabal > release. If you encounter this issue you might consider installing Cabal > and cabal-install from git. > > Lastly, I'd like to take a moment to acknowledge Futureice [2], who have > donated a brand new Mac Mini for use by GHC developers to help support > this platform. Their generosity is the reason we are able to offer OS X > builds to you today. > > Many thanks to Futureice for this donation! > > Happy testing! > > Cheers, > > - Ben > > > [1] > https://github.com/haskell/cabal/commit/1c1228a808b55331ac1db6d71fd2f8533f5… > [2] http://futurice.com/ > > _______________________________________________ > ghc-devs mailing list > ghc-devs(a)haskell.org > http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs > >

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new Typeable story
by Richard Eisenberg 21 Nov '15

21 Nov '15

Hi Simon, I'm a bit confused by the new handling of Typeable. * You say (in Note [Grand plan for Typeable]) that there is trouble making the TyCon/Module information for the types in GHC.Types. But what precisely goes wrong? I agree that it seems a bit fishy, but I don't actually see the spot where trouble lurks. Did you try this? * Even more bizarre would be putting TyCon/Module info for GHC.Prim stuff (I'm thinking about the super-magical TYPE) right in GHC.Prim. But still I can't quite articulate what goes wrong. There is no Prim.hi file that would be wonky. And, provided that GHC.Types itself doesn't try to solve a Typeable constraint, no one would ever notice the weird dependency. I recognize that this means we'd have to build the info somewhere manually in GHC, but I don't think that would be too hard -- and I think easier than the current story around name-mangling just so that you can write the typereps by hand in Data.Typeable.Internal. There's also not very many lifted tycons in GHC.Prim. I count TYPE and RealWorld, and that's it. For what it's worth, a weird dependency from GHC.Prim to GHC.Types actually works in practice. I put Levity in GHC.Types but (TYPE :: Levity -> TYPE 'Lifted) in GHC.Prim. No one complained. * Let's assume that we really can't clean up this mess. It still seems that several TyCons are missing from Data.Typeable.Internal. Like promoted nil and cons, and Nat, and Symbol. At the least, we should put a loud comment in the export list of GHC.Types saying that everything defined there must be accompanied by a definition in Data.Typeable.Internal. What do you think? Richard

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Re: Proposal: accept pull requests on GitHub
by Thomas Miedema 20 Nov '15

20 Nov '15

> > The real hint is that "the number of contributions will go up". That's > a noble goal and I think it's at the heart of this proposal. > It's not. What's at the heart of my proposal is that `arc` sucks. Most of those quotes I posted are from regular contributors (here's another one: "arcanist kinda makes stuff even more confusing than Git by itself"). Newcomers will give it their best shot, thinking it's just another thing they need to learn, thinking it's their fault for running into problems, thinking they'll get the hang of it eventually. Except they won't, or at least I haven't, after using it for over a year. Maybe the fundamental problem with Phabricator is that it doesn't understand Git well, and the problems I posted on https://ghc.haskell.org/trac/ghc/wiki/WhyNotPhabricator are just symptoms of it. I'm having trouble putting this into words though (something about branches and submodules). Perhaps someone else can? In my opinion it's is a waste of our time trying to improve `arc` (it is 34000 lines of PHP btw + another 70000 LOC for libphutil), when `pull requests` are an obvious alternative that most of the Haskell community already uses. When you're going to require contributors to use a non-standard tool to get patches to your code review system, it better just work. `arc` is clearly failing us here, and I'm saying enough is enough. I need to think about your other points. Thank you for the thorough reply. > Here's the meat of it question: what is the cost of achieving this > goal? That is, what amount of work is sufficient to make this goal > realizable, and finally - why is GitHub *the best use of our time for > achieving this?* That's one aspect of the cost - that it's the best > use of the time. I feel like this is fundamentally why I always seem > to never 'get' this argument, and I'm sure it's very frustrating on > behalf of the people who have talked to me about it and like GitHub. > But I feel like I've never gotten a straight answer for GHC. > > If the goal is actually "make more people contribute", that's pretty > broad. I can make that very easy: give everyone who ever submits a > patch push access. This is a legitimate way to run large projects that > has worked. People will almost certainly be more willing to commit, > especially when overhead on patch submission is reduced so much. Why > not just do that instead? It's not like we even mandate code review, > although we could. You could reasonably trust CI to catch and revert > things a lot of the time for people who commit directly to master. We > all do it sometimes. > > I'm being serious about this. I can start doing that tomorrow because > the *cost is low*, both now and reasonably speaking into some > foreseeable future. It is one of many solutions to raw heart of the > proposal. GitHub is not a low cost move, but also, it is a *long term > cost* because of the technical deficiencies it won't aim to address > (merge commits are ugly, branch reviews are weak, ticket/PR namespace > overlaps with Trac, etc etc) or that we'll have to work around. > > That means that if we want GitHub to fix the "give us more > contributors" problem, and it has a high cost, it not only has _to fix > the problem_, it also has to do that well enough to offset its cost. I > don't think it's clear that is the case right now, among a lot of > other solutions. > > I don't think the root issue is "We _need_ GitHub to get more > contributors". It sounds like the complaint is more "I don't like how > Phabricator works right now". That's an important distinction, because > the latter is not only more specific, it's more actionable: > > - Things like Arcanist can be tracked as a Git submodule. There is > little to no pain in this, it's low cost, and it can always be > synchronized with Phabricator. This eliminates the "Must clone > arcanist" and "need to upgrade arcanist" points. > > - Similarly when Phabricator sometimes kills a lot of builds, it's > because I do an upgrade. That's mostly an error on my part and I can > simply schedule upgrades regularly, barring hotfixes or somesuch. That > should basically eliminate these. The other build issues are from > picking the wrong base commit from the revision, I think, which I > believe should be fixable upstream (I need to get a solid example of > one that isn't a mega ultra patch.) > > - If Harbormaster is not building dependent patches as mentioned in > WhyNotPhabricator, that is a bug, and I have not been aware of it. > Please make me aware of it so I can file bugs! I seriously don't look > at _every_ patch, I need to know this. That could have probably been > fixed ASAP otherwise. > > - We can get rid of the awkwardness of squashes etc by using > Phabricator's "immutable" history, although it introduces merge > commits. Whether this is acceptable is up to debate (I dislike merge > commits, but could live with it). > > - I do not understand point #3, about answering questions. Here's > the reality: every single one of those cases is *almost always an > error*. That's not a joke. Forgetting to commit a file, amending > changes in the working tree, and specifying a reviewer are all total > errors as it stands today. Why is this a minus? It catches a useful > class of 'interaction bugs'. If it's because sometimes Phabricator > yells about build arifacts in the tree, those should be .gitignore'd. > If it's because you have to 'git stash' sometimes, this is fairly > trivial IMO. Finally, specifying reviewers IS inconvenient, but > currently needed. We could easily assign a '#reviewers' tag that would > add default reviewers. > - In the future, Phabricator will hopefully be able to > automatically assign the right reviewers to every single incoming > patch, based on the source file paths in the tree, using the Owners > tool. Technically, we could do that today if we wanted, it's just a > little more effort to add more Herald rules. This will be far, far > more robust than anything GitHub can offer, and eliminates point #3. > > - Styling, linting etc errors being included, because reviews are > hard to create: This is tangential IMO. We need to just bite the > bullet on this and settle on some lint and coding styles, and apply > them to the tree uniformly. The reality is *nobody ever does style > changes on their own*, and they are always accompanied by a diff, and > they always have to redo the work of pulling them out, Phab or not. > Literally 99% of the time we ask for this, it happens this way. > Perhaps instead we should just eliminate this class of work by just > running linters over all of the source code at once, and being happy > with it. > > Doing this in fact has other benefits: like `arc lint` will always > _correctly_ report when linting errors are violated. And we can reject > patches that violate them, because they will always be accurate. > > - As for some of the quotes, some of them are funny, but the real > message lies in the context. :) In particular, there have been several > cases (such as the DWARF work) where the idea was "write 30 commits > and put them on Phabricator". News flash: *this is bad*, no matter > whether you're using Phabricator or not, because it makes reviewing > the whole thing immensely difficult from a reviewer perspective. The > point here is that we can clear this up by being more communicative > about what we expect of authors of large patches, and communicating > your intent ASAP so we can get patches in as fast as possible. Writing > a patch is the easiest part of the work. > > And more: > > - Clean up the documentation, it's a mess. It feels nice that > everything has clear, lucid explanations on the wiki, but the wiki is > ridiculously massive and we have a tendancy for 'link creep' where we > spread things out. The contributors docs could probably stand to be > streamlined. We would have to do this anyway, moving to GitHub or not. > > - Improve the homepage, directly linking to this aforementioned page. > > - Make it clear what we expect of contributors. I feel like a lot of > this could be explained by having a 5 minute drive-by guide for > patches, and then a longer 10-minute guide about A) How to style > things, B) How to format your patches if you're going to contribute > regularly, C) Why it is this way, and D) finally links to all the > other things you need to know. People going into Phabricator expecting > it to behave like GitHub is a problem (more a cultural problem IMO but > that's another story), and if this can't be directly fixed, the best > thing to do is make it clear why it isn't. > > Those are just some of the things OTTOMH, but this email is already > way too long. This is what I mean though: fixing most of these is > going to have *seriously smaller cost* than moving to GitHub. It does > not account for "The GitHub factor" of people contributing "just > because it's on GitHub", but again, that value has to outweigh the > other costs. I'm not seriously convinced it does. > > I know it's work to fix these things. But GitHub doesn't really > magically make a lot of our needs go away, and it's not going to > magically fix things like style or lint errors, the fact Travis-CI is > still pretty insufficient for us in the long term (and Harbormaster is > faster, on our own hardware, too), or that it will cause needlessly > higher amounts of spam through Trac and GitHub itself. I don't think > settling on it as - what seems to be - a first resort, is a really > good idea. > > > On Wed, Sep 2, 2015 at 4:09 PM, Niklas Hambüchen <mail(a)nh2.me> wrote: > > On 02/09/15 22:42, Kosyrev Serge wrote: > >> As a wild idea -- did anyone look at /Gitlab/ instead? > > > > Hi, yes. It does not currently have a sufficient review functionality > > (cannot handle multiple revisions easily). > > > > On 02/09/15 20:51, Simon Marlow wrote: > >> It might feel better > >> for the author, but discovering what changed between two branches of > >> multiple commits on github is almost impossible. > > > > I disagree with the first part of this: When the UI of the review tool > > is good, it is easy to follow. But there's no open-source implementation > > of that around. > > > > I agree that it is not easy to follow on Github. > > _______________________________________________ > > ghc-devs mailing list > > ghc-devs(a)haskell.org > > http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs > > > > > > -- > Regards, > > Austin Seipp, Haskell Consultant > Well-Typed LLP, http://www.well-typed.com/ > _______________________________________________ > ghc-devs mailing list > ghc-devs(a)haskell.org > http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs >

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