Yaml file not found when Windows username contains non-ASCII characters

[Forkest]

I'm encountering the same issue as described here.

Almost any stack command (except of stack --version) results in an output like this (user René here):

Could not parse 'C:\Users\Ren├®\AppData\Roaming\stack\config.yaml':
InvalidYaml (Just (YamlException "Yaml file not found: C:\\Users\\Ren\233\\AppData\\Roaming\\stack\\config.yaml"))
See http://docs.haskellstack.org/en/stable/yaml_configuration.html.

The file is recreated successfully when I delete it, so in theory it should be possible to read it too.

[Blaisorblade]

First, thanks for the report! Can you run a failing command with -v and post the complete log?

Then, have you tried the final tip on STACK_ROOT, as a workaround?
https://stackoverflow.com/questions/34905113/how-to-change-the-default-location-of-stack-yaml-on-windows#comment57558955_34905113

EDIT: I've just found your comment confirming STACK_ROOT works, sorry for the noise.

but it worked when i set the environment varibale manually in the windows system settings

[Blaisorblade]

Already minimized to a bug in the Yaml library.

René/foo.yaml

true
...

testYaml.hs:

import qualified Data.Yaml as Yaml

loadYaml :: FilePath -> IO (Either Yaml.ParseException Bool)
loadYaml = Yaml.decodeFileEither

main :: IO ()
main = do
  print =<< loadYaml "René\\foo.yaml"
  return ()

$ stack runhaskell testYaml.hs
Left (InvalidYaml (Just (YamlException "Yaml file not found: Ren\233\\foo.yaml")))

What I've shown is on a fresh Win10 VM, insideGit Bash coming from Git for Windows.

[Blaisorblade]

Oh dear. Data.Yaml is a wrapper over a C library, but the issue is probably in its FFI code. I've filed an analysis over there. It doesn't appear fixed in later versions, but I haven't tried.

I think the easiest workaround doable inside stack is to read the file in Haskell into a bytestring and call — even if this changes the space complexity, stack.yaml files are probably usually small enough that this doesn't matter.

[Blaisorblade]

Re workaround: since Snoyberg is in vacation, I guess we shouldn't expect a quickfix upstream. https://twitter.com/snoyberg/status/764514619822051328

[Blaisorblade]

It turns out I got two fixes:

• Handle non-ASCII filenames correctly on Windows snoyberg/yaml#91, under review externally (even though Snoyberg is on vacation he reacted to my bug report).
• a workaround through Workaround #2491 at all call sites #2492 (that somehow is failing on Windows though, I didn't check because I was working on the other fix, investigating now O_O).

[Blaisorblade]

@Forkest #2492 is merged so this should be fixed on master. Hence closing.