Cabal unusable in Windows when username has unicode characters

[alt-romes]

Describe the bug
Cabal becomes unusable in Windows when the username has unicode characters (that is my suspicion), because attempts to read e.g. the global config fail.

To Reproduce

Daniel João@DESKTOP-PBTBE76 MINGW64 /tmp/tmp.UvhafQVlZ0/ghc
$ cabal --store-dir=$(pwd)/store install alex-3.5.0.0 happy --installdir=$(pwd)/bin
Config file path source is default config file.
Config file not found: C:\Users\Daniel Jo?o\AppData\Roaming\cabal\config
Writing default configuration to C:\Users\Daniel
Jo?o\AppData\Roaming\cabal\config
C:\Users\Daniel Jo?o\AppData\Roaming\cabal\config.tmp: withFile: invalid argument (invalid character)

System information

• Operating system: Windows Mingw-w64-x86_64
• cabal, ghc versions: ghc 9.8.2, cabal 3.10.3

[ffaf1]

Do you know whether the config data was already present?

It would be failure to write rathern than read.

It would be lovely if some Win users could replicate this.

[alt-romes]

The config file was not present, it was a clean unused install.