Cabal cannot register a package in a directory with Unicode chars

While fixing #5697 (closed), I tried building and registering a package in a directory with Unicode chars, and cabal-install fails to register it.

This appears to be a regression since 7.0, as it first fails with 7.2 and is still failing in 7.4.

I'm not sure who's fault this is, but since it is GHC-version dependent it could well be ours.

c:\simonmar\scratch\áéóíúúíáλ>cabal register --inplace -v
c:\simonmar\ghc-validate\inplace\bin\ghc-stage2.exe --abi-hash -package-name par
allel-3.2.0.0 -hide-all-packages -fbuilding-cabal-package -i -idist\build -i. -i
dist\build\autogen -Idist\build\autogen -Idist\build -optP-include -optPdist\bui
ld\autogen\cabal_macros.h -odir dist\build -hidir dist\build -stubdir dist\build
 -package-id array-0.3.0.3-inplace -package-id base-4.4.0.0-inplace -package-id
containers-0.4.2.0-inplace -package-id deepseq-1.2.0.1-inplace -O -feager-blackh
oling -Wall -XCPP -XBangPatterns Control.Seq Control.Parallel Control.Parallel.S
trategies
Registering parallel-3.2.0.0...
c:\simonmar\ghc-validate\inplace\bin\ghc-pkg.exe update - --global --user
cabal: fd:5: hGetContents: invalid argument (invalid UTF-8 byte sequence)
cabal: fd:5: invalid argument

I tried with cabal-install 0.8 and 0.10:

c:\simonmar\scratch\áéóíúúíáλ>cabal --version
cabal-install version 0.10.2
using version 1.10.2.0 of the Cabal library

c:\simonmar\scratch\áéóíúúíáλ>cabal +RTS --info
 [("GHC RTS", "YES")
 ,("GHC version", "7.0.4")
 ,("RTS way", "rts_v")
 ,("Build platform", "i386-unknown-mingw32")
 ,("Build architecture", "i386")
 ,("Build OS", "mingw32")
 ,("Build vendor", "unknown")
 ,("Host platform", "i386-unknown-mingw32")
 ,("Host architecture", "i386")
 ,("Host OS", "mingw32")
 ,("Host vendor", "unknown")
 ,("Target platform", "i386-unknown-mingw32")
 ,("Target architecture", "i386")
 ,("Target OS", "mingw32")
 ,("Target vendor", "unknown")
 ,("Word size", "32")
 ,("Compiler unregisterised", "NO")
 ,("Tables next to code", "YES")
 ]

I haven't tried building cabal-install with 7.2 yet.

Trac metadata

Trac field	Value
Version	7.2.1
Type	Bug
TypeOfFailure	OtherFailure
Priority	highest
Resolution	Unresolved
Component	Package system
Test case
Differential revisions
BlockedBy
Related
Blocking
CC	duncan
Operating system	Unknown/Multiple
Architecture