Brittany strips shebangs

[pbrisbin]

% brittany --version
brittany version 0.11.0.0
Copyright (C) 2016-2018 Lennart Spitzner
There is NO WARRANTY, to the extent permitted by law.

Example

/tmp/script

#!/usr/bin/env stack
{- stack script --resolver lts -}
module Main where

import AnotherModule
import Data.Text

main :: IO ()
main = undefined

Expected

% brittany /tmp/script
#!/usr/bin/env stack
{- stack script --resolver lts -}
module Main where

import AnotherModule
import Data.Text

main :: IO ()
main = undefined

(Shebang preserved.)

Actual

% brittany /tmp/script

{- stack script --resolver lts -}
module Main where

import AnotherModule
import Data.Text

main :: IO ()
main = undefined

(The shebang was stripped.)

---

This makes brittany unusable for so-called "Stack Scripts", which are becoming quite popular.

[tfausak]

I think this is related to #92. I tried using both STDIN and a file; both worked. Can you try again and reopen this if it's still a problem? Thanks!

[pbrisbin]

I think this has regressed, specifically on usage with a file:

% stack exec brittany -- --version
brittany version 0.12.0.0
Copyright (C) 2016-2018 Lennart Spitzner
There is NO WARRANTY, to the extent permitted by law.
% stack exec brittany < ./scripts/hello
#!/usr/bin/env stack
-- stack script --resolver lts-15.4
-- vim: ft=haskell
module Main
  ( main
  )
where

main :: IO ()
main = putStrLn "Hello"
% stack exec brittany ./scripts/hello

-- stack script --resolver lts-15.4
-- vim: ft=haskell
module Main
  ( main
  )
where

main :: IO ()
main = putStrLn "Hello"

Can we re-open?

[tfausak]

Seems like this has been fixed again:

# cat issue-192.hs 
#! /usr/bin/env stack
-- stack --resolver lts-16.0 script
main = pure ()

# brittany issue-192.hs 
#! /usr/bin/env stack
-- stack --resolver lts-16.0 script
main = pure ()

# brittany --version
brittany version 0.12.1.1
Copyright (C) 2016-2019 Lennart Spitzner
Copyright (C) 2019 PRODA LTD
There is NO WARRANTY, to the extent permitted by law.

[pbrisbin]

Nice, thanks!

[pbrisbin]

👋 It's me again... This bug seems to still occur, but only if you invoke it with a certain kind of path.

% cat issue-192.hs
#!/usr/bin/env stack
-- stack --resolver lts-16.0 script
main = pure ()
% stack exec brittany -- --version
brittany version 0.12.1.1
Copyright (C) 2016-2019 Lennart Spitzner
Copyright (C) 2019 PRODA LTD
There is NO WARRANTY, to the extent permitted by law.

% stack exec brittany -- issue-192.hs
#!/usr/bin/env stack
-- stack --resolver lts-16.0 script
main = pure ()
% stack exec brittany -- ./issue-192.hs

-- stack --resolver lts-16.0 script#!/usr/bin/env stack

main = pure ()

So, issue-192.hs works, but ./issue-192.hs doesn't work.

The bug also triggers on absolute paths or relative paths outside the current directory, but only if you ./ prefix them as well.

% stack exec brittany -- x/issue-192.hs
#!/usr/bin/env stack
-- stack --resolver lts-16.0 script
main = pure ()
% stack exec brittany -- ./x/issue-192.hs

-- stack --resolver lts-16.0 script#!/usr/bin/env stack

main = pure ()

% stack exec brittany -- ../../brittany-repro/issue-192.hs

-- stack --resolver lts-16.0 script#!/usr/bin/env stack

main = pure ()

🤷

My editor plugin (ALE in vim) uses an absolute path to a tempfile, which is why the bug bites me so frequently.

[tfausak]

Oh dear. That's super weird.

[pbrisbin]

FYI, this seems to be the root cause: alanz/ghc-exactprint#92 I got bit in HLint too (via apply-refact, via ghc-exact-print, which I believe Brittany uses as well).

[tfausak]

This has been fixed.