Delaying 7.10?

[Carter Schonwald]

additionally, the bug seems to work in GHC 7.8.4 too.

On Thu, Jan 29, 2015 at 5:07 PM, Edward Kmett <ekmett at gmail.com> wrote:

> I personally would rather see this issue given the time to be resolved
> correctly than rush to release 7.10 now because of a self-imposed deadline.
>
> An unsafeCoerce bug, especially one which affects SafeHaskell, pretty much
> trumps all in my eyes.
>
> -Edward
>
> On Thu, Jan 29, 2015 at 2:54 PM, Austin Seipp <austin at well-typed.com>
> wrote:
>
>> After thinking about it a little, I'm fine with pushing the release out
>> to March. I think #9858 is the more serious of our concerns vs a raging
>> debate, too.
>>
>> My only concern really is dealing with the merging of such a patch. For
>> example, if the patch to fix this is actually as wide ranging as we believe
>> to the type hacker, I can definitely foresee a merge conflict, with, say,
>> the recent -fwarn-redundant-constraints, which I've managed to leave out of
>> 7.10 so far.
>>
>> In any case, with some more time, we can work those details out.
>>
>> On Thursday, January 29, 2015, Simon Peyton Jones <simonpj at microsoft.com>
>> wrote:
>>
>>>  Friends
>>>
>>> In a call with a bunch of type hackers, we were discussing
>>>
>>>                https://ghc.haskell.org/trac/ghc/ticket/9858
>>>
>>> This is a pretty serious bug.  It allows a malicious person to construct
>>> his own unsafeCoerce, and so completely subverts Safe Haskell.
>>>
>>> Actually there are two bugs (see comment:19).  The first is easily
>>> fixed.  But the second is not.
>>>
>>> We explored various quick fixes, but the real solution is not far out of
>>> reach.  It amounts to this:
>>>
>>> ·        Every data type is automatically in Typeable.  No need to say
>>> “deriving(Typeable)” or “AutoDeriveTypeable” (which would become deprecated)
>>>
>>> ·        In implementation terms, the constraint solver treats Typeable
>>> specially, much as it already treats Coercible specially.
>>>
>>> It’s not a huge job.  It’d probably take a couple of days of
>>> implementation work, and some time for shaking out bugs and consequential
>>> changes.  The biggest thing might be simply working out implementation
>>> design choices.  (For example, there is a modest code-size cost to making
>>> everything Typeable, esp because that includes the data constructors of the
>>> type (which can be used in types, with DataKinds).  Does that matter?
>>> Should we provide a way to suppress it?  If so, we’d also need a way to
>>> express whether or not the Typable instance exists in the interface file.)
>>>
>>> But it is a substantial change that will touch a lot of lines of code.
>>> Moreover, someone has to do it, and Iavor (who heroically volunteered)
>>> happens to be travelling next week.
>>>
>>> So it’s really not the kind of thing we would usually do after RC2.
>>>
>>> But (a) it’s serious and, as it happens, (b) there is also the BBP
>>> Prelude debate going on.
>>>
>>> Hence the question: should we simply delay 7.10  by, say, a month?
>>> After all, the timetable is up to us.  Doing so might give a bit more
>>> breathing space to the BBP debate, which might allow time for reflection
>>> and/or implementation of modest features to help the transition.  (I know
>>> that several are under discussion.)  Plus, anyone waiting for 7.10 can
>>> simply use RC2, which is pretty good.
>>>
>>> Would that be a relief to the BBP debate?  Or any other opinions.
>>>
>>> Simon
>>>
>>> PS: I know, I know: there is endless pressure to delay releases to get
>>> stuff in.  If we give in to that pressure, we never make a release.  But we
>>> should know when to break our own rules.  Perhaps this is such an occasion.
>>>
>>
>>
>> --
>> Regards,
>>
>> Austin Seipp, Haskell Consultant
>> Well-Typed LLP, http://www.well-typed.com/
>>
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>>
>
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