`haskell-stylish-on-save` with Yasnippet + ghc-mod sometimes removes import list

[konn]

Using haskell-stylish-on-save with Yasnippet's import snippet sometimes erases import list. It seems that this occur when the import order will be changes.

Example:

module Main where
import Prelude
imp

Then hit [TAB] on right after imp and import Language.Haskell.TH using ghc-mod's function symbol completion:

module Main where
import Prelude
import Language.Haskell.TH

Push [TAB] to exit snippet, and don't move caret from right after TH.
Hit C-xC-s, then import list vanishes!:

module Main where
import 

Environment

• GNU Emacs 24.3.4 (x86_64-apple-darwin11.4.2, Carbon Version 1.6.0 AppKit 1138.51)
• yasnippet-20140314
• haskell-mode-20140330
• ghc-20140331

[chrisdone]

Maybe the buffer isn't being saved so stylish-haskell is working on an old version?

[gracjan]

This issue has not seen activity for a very long time. Is this still something we should be concerned about?

[lukehoersten]

Yes this is definitely still a problem. Until I saw this just now I didn't know it was related to YAS.

[gracjan]

@DanielG: Can you have a look at this if it has possibly any connection with ghc-mod?

[DanielG]

I don't see anything in the code that would trigger this sort of behavior immediately but I don't have enough time to reproduce this, I tried but I can't get haskell-mode to behave in a minimal environment for some reason :/. If we have a testcase I can give it a proper look.

[gracjan]

@lukehoersten: have you actually reproduced the problem or not?

[lukehoersten]

@gracjan I was able to reproduce, yes.

[gracjan]

What about this one?

[lukehoersten]

Still happens though I have no idea why. Happens maybe 1 out of 10 times but it's pretty reproducible.