1 files changed, 31 insertions, 0 deletions
diff --git a/libraries/ghc-boot/GHC/HandleEncoding.hs b/libraries/ghc-boot/GHC/HandleEncoding.hs
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+++ b/libraries/ghc-boot/GHC/HandleEncoding.hs
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+-- | See GHC #10762 and #15021.
+module GHC.HandleEncoding (configureHandleEncoding) where
+
+import GHC.IO.Encoding (textEncodingName)
+import System.Environment
+import System.IO
+
+-- | Handle GHC-specific character encoding flags, allowing us to control how
+-- GHC produces output regardless of OS.
+configureHandleEncoding :: IO ()
+configureHandleEncoding = do
+   env <- getEnvironment
+   case lookup "GHC_CHARENC" env of
+    Just "UTF-8" -> do
+     hSetEncoding stdout utf8
+     hSetEncoding stderr utf8
+    _ -> do
+     -- Avoid GHC erroring out when trying to display unhandled characters
+     hSetTranslit stdout
+     hSetTranslit stderr
+
+-- | Change the character encoding of the given Handle to transliterate
+-- on unsupported characters instead of throwing an exception
+hSetTranslit :: Handle -> IO ()
+hSetTranslit h = do
+    menc <- hGetEncoding h
+    case fmap textEncodingName menc of
+        Just name | '/' `notElem` name -> do
+            enc' <- mkTextEncoding $ name ++ "//TRANSLIT"
+            hSetEncoding h enc'
+        _ -> return ()