[commit: haddock] ghc-head, ghc-head1, headdock-library-1.4.5, ie_avails, master, pr/cabal-desc, v2.18, wip/T14529, wip/revert-ttg-2017-11-20, wip/ttg-2017-10-13, wip/ttg-2017-10-31, wip/ttg-2017-11-06, wip/ttg2-2017-11-10, wip/ttg3-2017-11-12, wip/ttg4-constraints-2017-11-13, wip/ttg6-unrevert-2017-11-22: Avoid errors on non UTF-8 Windows (#566) (22cbf4d)

[git at git.haskell.org]

Repository : ssh://git@git.haskell.org/haddock

On branches: ghc-head,ghc-head1,headdock-library-1.4.5,ie_avails,master,pr/cabal-desc,v2.18,wip/T14529,wip/revert-ttg-2017-11-20,wip/ttg-2017-10-13,wip/ttg-2017-10-31,wip/ttg-2017-11-06,wip/ttg2-2017-11-10,wip/ttg3-2017-11-12,wip/ttg4-constraints-2017-11-13,wip/ttg6-unrevert-2017-11-22
Link       : http://git.haskell.org/haddock.git/commitdiff/22cbf4d9509d3b537e6c2fcf4c95ae73d930b9aa

>---------------------------------------------------------------

commit 22cbf4d9509d3b537e6c2fcf4c95ae73d930b9aa
Author: Yuji Yamamoto <whosekiteneverfly at gmail.com>
Date:   Tue Jul 4 23:13:12 2017 +0900

    Avoid errors on non UTF-8 Windows (#566)
    
    * Avoid errors on non UTF-8 Windows
    
    Problem
    ====
    
    haddock exits with errors like below:
    
    `(1)`
    
    ```
    haddock: internal error: <stderr>: hPutChar: invalid argument (invalid character)
    ```
    
    `(2)`
    
    ```
    haddock: internal error: Language\Haskell\HsColour\Anchors.hs: hGetContents: invalid argument (invalid byte sequence)
    ```
    
    `(1)` is caused by printing [the "bullet" character](http://www.fileformat.info/info/unicode/char/2022/index.htm) onto stderr.
    For example, this warning contains it:
    
    ```
    Language\Haskell\HsColour\ANSI.hs:62:10: warning: [-Wmissing-methods]
        • No explicit implementation for
            ‘toEnum’
        • In the instance declaration for ‘Enum Highlight’
    ```
    
    `(2)` is caused when the input file of `readFile` contains some Unicode characters.
    In the case above, '⇒' is the cause.
    
    Environment
    ----
    
    OS: Windows 10
    haddock: 2.17.3
    GHC: 8.0.1
    
    Solution
    ====
    
    Add `hSetEncoding handle utf8` to avoid the errors.
    
    Note
    ====
    
    - I found the detailed causes by these changes for debugging:
        - https://github.com/haskell/haddock/commit/8f29edb6b02691c1cf4c479f6c6f3f922b35a55b
        - https://github.com/haskell/haddock/commit/1dd23bf2065a1e1f2c14d0f4abd847c906b4ecb4
    - These errors happen even after executing `chcp 65001` on the console.
      According to the debug code, `hGetEncoding stderr` returns `CP932` regardless of the console encoding.
    
    * Avoid 'internal error: <stderr>: hPutChar: invalid argument (invalid character)' non UTF-8 Windows
    
    Better solution for 59411754a6db41d17820733c076e6a72bcdbd82b's (1)


>---------------------------------------------------------------

22cbf4d9509d3b537e6c2fcf4c95ae73d930b9aa
 haddock-api/src/Haddock/Interface.hs | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/haddock-api/src/Haddock/Interface.hs b/haddock-api/src/Haddock/Interface.hs
index 62b0aea..cdc3064 100644
--- a/haddock-api/src/Haddock/Interface.hs
+++ b/haddock-api/src/Haddock/Interface.hs
@@ -1,3 +1,4 @@
+{-# LANGUAGE CPP #-}
 -----------------------------------------------------------------------------
 -- |
 -- Module      :  Haddock.Interface
@@ -48,14 +49,20 @@ import qualified Data.Set as Set
 import Distribution.Verbosity
 import System.Directory
 import System.FilePath
+import System.IO
 import Text.Printf
 
 import Digraph
 import DynFlags hiding (verbosity)
 import Exception
 import GHC hiding (verbosity)
+#if defined(mingw32_HOST_OS)
+import GHC.IO.Encoding.CodePage (mkLocaleEncoding)
+import GHC.IO.Encoding.Failure (CodingFailureMode(TransliterateCodingFailure))
+#endif
 import HscTypes
 import FastString (unpackFS)
+import MonadUtils (liftIO)
 
 -- | Create 'Interface's and a link environment by typechecking the list of
 -- modules using the GHC API and processing the resulting syntax trees.
@@ -68,6 +75,10 @@ processModules
   -> Ghc ([Interface], LinkEnv) -- ^ Resulting list of interfaces and renaming
                                 -- environment
 processModules verbosity modules flags extIfaces = do
+#if defined(mingw32_HOST_OS)
+  -- Avoid internal error: <stderr>: hPutChar: invalid argument (invalid character)' non UTF-8 Windows
+  liftIO $ hSetEncoding stderr $ mkLocaleEncoding TransliterateCodingFailure
+#endif
 
   out verbosity verbose "Creating interfaces..."
   let instIfaceMap =  Map.fromList [ (instMod iface, iface) | ext <- extIfaces