cabal doesn't handle error conditions from getAppUserDataDirectory

[bos]

(Imported from Trac #709, reported by @creswick on 2010-07-12)

Distribution.Simple.InstallDirs.defaultInstallDirs fails if getAppUserDataDirectory fails, and it does so with a very uninformative error:

# On Cabal 1.8.0.2:
cabal.exe: illegal operation

This is a slight regression from the HP 2009 version:

# On Cabal 1.6.0.3:
cabal.exe: System.Directory.getAppUserDataDirectory: unsupported operation (unsupported operation)

This happens on Windows Vista, in cygwin, when the user doesn't have a windows user directory (eg: c:\users\username).

[bos]

(Imported comment by @creswick on 2010-07-12)

This can be recreated with a windows vista system that has cygwin and a cygwin ssh server running:

• Add a new windows user (say 'testUser'), but do not log in with that user.
• ssh to the host as testUser
• attempt to run cabal with some sort of command line parameters (eg: cabal --help)

[bos]

(Imported comment by @dcoutts on 2010-07-13)

I suppose we could improve the error message but I don't see that we can make anything work if getAppUserDataDirectory fails. It means we cannot read the config file.

The error message issue could do with some work. We should make sure the topHandler is not throwing useful information away.

[neongreen]

In case anyone has the same problem and stumbles upon this comment: if your Windows user name contains non-latin letters (to be more precise: if the name of your home directory contains non-latin letters), and you're using MSYS, you'll get this error.

[ttuegel]

@neongreen Is this a problem if you aren't using MSYS?

[jasagredo]

This ticket talks about Cygwin. Haskell nowadays is based on Mingw. I am preemptively closing this, please reopen otherwise.