Odd GHCi behavior

[Donald Bruce Stewart]

ketil:
> Andy Moran <moran at galois.com> writes:
> 
> > Skipping  Util.List        ( ../../libraries/Util/List.hs, 
> > ../../libraries/Util/List.o )
> > ...
> 
> > Failed to load interface for `Util.List':
> 
> > Doing a big old clean, --make, and then GHCi solved the problem.  But what 
> > could cause this kind of behavior?  (I can't reproduce it, sorry.)
> 
> Something similar has occasionally happened to me when I've
> interrupted (^C) a build.  Presumably, the compiler gets around to
> touching the relevant file(s), but stops before it is able to finish
> them, and doesn't clean up.


I've seen this occasionally on private nightly builds over an
NFS link. Only over NFS. But this hasn't happened since 6.0.1. It 
would happen one night, and not the next, even if nothing changed
in the source. So I always presumed it was a weird timestamp
issue.

Now, looking in my old build logs... aaha! I found it! It only
ever happened in nofib builds. Here is an example:

  ------------------------------------------------------------

    ==nofib== infer: time to compile InferMonad follows...
    /home/pls/src/ghc6+stix/nightly/i386-unknown-linux/ghc/compiler/stage3/ghc-inplace -H16m -O -O -funbox-strict-fields -fexcess-precision -Rghc-timing -H32m -hisuf hi -cpp -c InferMonad.hs -o InferMonad.o

    InferMonad.hs:6:
        Failed to load interface for `StateX':
        Could not find interface file for `StateX'
        (use -v to see a list of the files searched for)

    InferMonad.hs:6: Module `StateX' does not export `StateX'

    InferMonad.hs:6: Module `StateX' does not export `returnSX'

    InferMonad.hs:6: Module `StateX' does not export `eachSX'

    InferMonad.hs:6: Module `StateX' does not export `thenSX'

    InferMonad.hs:6: Module `StateX' does not export `toSX'

    InferMonad.hs:6: Module `StateX' does not export `putSX'

    InferMonad.hs:6: Module `StateX' does not export `getSX'
     
    InferMonad.hs:6: Module `StateX' does not export `useSX'

    InferMonad.hs:8:
        Failed to load interface for `Substitution':
        Could not find interface file for `Substitution'
        (use -v to see a list of the files searched for)

  ------------------------------------------------------------

Etc., etc. If someone finds this useful, the entire nightly build
logs from that night are available online at:

    ftp.cse.unsw.edu.au/pub/users/dons/ghc+stix/logs/

Particularly, "i386-unknown-linux-nofib-5", which showed this
behaviour, although it has occured in other places.

Cheers,
    Don