no ghci in powerpc-based Ubuntu since edgy (regression vs dapper)

[Isaac Dupree]

Binary package hint: ghc6

ghci is the interpreter mode of GHC, the Glasgow Haskell Compiler.

In Dapper I could use GHCi. After upgrading to Edgy:
$ ghci
ghc-6.4.2: not built for interactive use

This also affects the runhaskell/runghc commands. This interferes with using the Haskell Cabal build infrastructure, although `runhugs +98 Setup.lhs [arguments...]`can be used instead to work around this particular problem. (The +98 is needed to work around a problem with the Haskell interpreter "hugs", but I'm not sure if /that's/ more Edgy's or Hugs's fault.)

IIRC, GHC needs to be built with the exact same version of itself in order for GHCi to work.

It's too bad edgy's ghc is only 6.4.2 not 6.6, but I suppose that (1) is irrelevant and (2) can't be changed now that Edgy is released.

[Isaac Dupree (idupree)]

Oops, I meant runhugs -98, not +98 -- its flags are so confusing. Probably this should be in a separate bug report somewhere, but, here is the messages I get for doing that the wrong way:
runhugs: Error occurred
ERROR "/usr/lib/hugs/libraries/Text/ParserCombinators/ReadP.hs":133 - Syntax error in type expression (unexpected `.')

[StefanPotyra (sistpoty)]

Hi,

what arch are you trying to use ghci on? (I'd guess it's neither i386 nor amd64). If so, it's intended that there is no more ghci, due to http://hackage.haskell.org/trac/ghc/ticket/631 .

Backporting ghc6.6 is not trivially done, the same comments I wrote on bug #56516 apply here as well :(.

Cheers,
    Stefan.

[Isaac Dupree (idupree)]

It's powerpc -- but surely GHC is built registerised on that architecture? (is there some way I can find out whether a given ghc binary was built that way?)

[Isaac Dupree (idupree)]

Rebooting into a copy of my OS from before upgrading from Dapper to Edgy, I can reproduce the referenced ghc-bug-631. So I see there is a reason for this. On the other hand, I didn't notice any problems when I used ghci, personally...

[StefanPotyra (sistpoty)]

Hi,

ghc6 on powerpc is not built registerized:
"Removed powerpc from the list of arches to do a registerised build with object splitting as there are bootstrapping issues from earlier GHCs." (Ian's changelog entry, 6.4-3).

You can also find this out by looking at debian/rules of the sourcepackage (line 39 and below).

I personally don't have access to a powerpc box, so I didn't change anything on that front (also I'm more than happy, that ghc6 itself actually works on all ubuntu arches).

If you know of a fix, or would like to help out in this matter, please do. However changing from unregisterised to registerised for edgy also won't work, since that would also mean that all haskell library packages would need to be rebuilt.

Thanks,
     Stefan.

[Chris Wagner (chris-wagner)]

Hey folks. Is anyone still hoping to do something about this issue? Or should we mark it as "won't fix"?

[Isaac Dupree (idupree)]

As long as GHC has no registerised-powerpc maintainer (which I believe is still true), and ghc bug #631 remains unfixed <http://hackage.haskell.org/trac/ghc/ticket/631> (even if it is fixed in GHC 6.8, that won't be out in time for Gutsy, but 6.8 will be in time for gutsy+1), I don't think this bug is going to be fixed. I think the best bet is to hope for #631 to be fixed soon, then let the Debian packagers turn on GHCi for the unregisterised architectures, and (if I understand the process correctly) Ubuntu can then inherit those changes from Debian as soon as practicable.

Although, I'm not sure how important "bootstrap issues with [(some particular)] older ghcs" are as time passes, in debian-ish environments, (and I'm not using ubuntu anymore either (for one thing, the two projects' release cycles and practices help Ubuntu be chronically behind by one on the newest GHC release...))

[John Steele Scott (toojays)]

I know this is pending on upstream & Debian activity, but just for the record this bug is still current on gutsy/powerpc.

[Isaac Dupree (idupree)]

well, the upstream bug seems to be fixed as of ghc-6.10.1, so it should be possible to enable GHCi in our/Debian's build as soon as ghc >= 6.10.1 rolls around for us

[Gianfranco Costamagna (costamagnagianfranco)]

Closing since ghc6 is not in ubuntu anymore.