Unknown symbol error when ghci tries to load package scion

[greenrd]

If you add scion to your flags in ~/.cabal/config, and then do the following:

git clone git://github.com/greenrd/scion.git
cd scion
git checkout devel   # DON'T OMIT THIS LINE!!!
cabal install
cd ..
darcs get --lazy http://code.haskell.org/yi/
cd yi

and then make the following change to yi.cabal

           -- requires an unreleased version atm.
 
         if flag (scion)
-          build-depends: ghc == 6.10.*
+          build-depends: ghc >= 6.10.1
           build-depends: ghc-syb
           build-depends: scion
           cpp-options: -DSCION

and then do cabal install, you should get, after some time, when it gets around to compiling yi itself:

Loading package multiset-0.2 ... linking ... done.
Loading package network-bytestring-0.1.2.1 ... linking ... done.
Loading package uniplate-1.4 ... linking ... done.
ghc: /home/greenrd/.cabal/lib/scion-0.1.0.3/ghc-6.12.1/HSscion-0.1.0.3.o: unknown symbol `scionzm0zi1zi0zi3_ScionziTypesziOutline_OutlineDef_con_info'
Loading package scion-0.1.0.3 ... linking ... ghc: unable to load package `scion-0.1.0.3'
cabal: Error: some packages failed to install:
yi-0.6.2.2 failed during the building phase. The exception was:
ExitFailure 1

(I had to make a couple of changes from upstream scion to make scion compile together with yi, and those are in my repository.)

Although, to save time, you probably DON'T need to go to the trouble of trying to compile yi - I'd hazard a guess that the bug occurs in the compilation of scion, not the compilation of yi.

I did "cabal clean" in the scion directory and tried again - same result.

[greenrd]

According to the nm utility, the _con_info symbol in question is defined in dist/build/Scion/Types/Outline.o, but undefined in dist/build/HSscion-0.1.0.3.o.

[simonmar]

Perhaps this is  http://trac.haskell.org/haddock/ticket/135?

[greenrd]

I don't think so - it's not building haddock docs, as far as I know. Also, it doesn't appear to use Template Haskell.

[simonmar]

After grabbing the git repo:

$ git checkout devel
error: pathspec 'devel' did not match any file(s) known to git.

I admit to not possessing a clue about git, what has gone wrong here?

[greenrd]

It works in git 1.7.0.1. Perhaps it's a new feature.

Try this instead:

git checkout -b devel origin/devel

[simonmar]

The module Scion.Types.Outline is missing from exposed-modules in scion.cabal.

[simonpj]

Yes, its really a bad Cabal bug that it lets you successfully build a Scion package that is missing one of its modules. The error only shows up when consumers use the package. Argh!

Simon