Normalize C:\\\\ to C:\ wrt #12

Author: hasufell

System/FilePath/Internal.hs

@@ -933,6 +933,7 @@ makeRelative root path
 -- > Posix:   normalise "./bob/fred/" == "bob/fred/"
 -- > Windows: normalise "c:\\file/bob\\" == "C:\\file\\bob\\"
 -- > Windows: normalise "c:\\" == "C:\\"
+-- > Windows: normalise "c:\\\\\\\\" == "C:\\"
 -- > Windows: normalise "C:.\\" == "C:"
 -- > Windows: normalise "\\\\server\\test" == "\\\\server\\test"
 -- > Windows: normalise "//server/test" == "\\\\server\\test"
@@ -984,9 +985,12 @@ normaliseDrive :: FILEPATH -> FILEPATH
 normaliseDrive bs
   | null bs = mempty
   | isPosix = pack [pathSeparator]
-  | otherwise = if isJust $ readDriveLetter x2
-         then map toUpper x2
-         else x2
+  | Just (drv, _) <- readDriveLetter x2
+                  = case unpack drv of
+                      (x:_:[]) -> pack [toUpper x, _colon]
+                      (x:_) -> pack [toUpper x, _colon, pathSeparator]
+                      _ -> P.error "impossible"
+  | otherwise = x2
     where
         x2 = map repSlash bs
         repSlash x = if isPathSeparator x then pathSeparator else x

tests/filepath-tests/TestGen.hs

@@ -812,6 +812,8 @@ tests =
     ,("AFP_W.normalise (\"c:\\\\file/bob\\\\\") == (\"C:\\\\file\\\\bob\\\\\")", property $ AFP_W.normalise ("c:\\file/bob\\") == ("C:\\file\\bob\\"))
     ,("W.normalise \"c:\\\\\" == \"C:\\\\\"", property $ W.normalise "c:\\" == "C:\\")
     ,("AFP_W.normalise (\"c:\\\\\") == (\"C:\\\\\")", property $ AFP_W.normalise ("c:\\") == ("C:\\"))
+    ,("W.normalise \"c:\\\\\\\\\\\\\\\\\" == \"C:\\\\\"", property $ W.normalise "c:\\\\\\\\" == "C:\\")
+    ,("AFP_W.normalise (\"c:\\\\\\\\\\\\\\\\\") == (\"C:\\\\\")", property $ AFP_W.normalise ("c:\\\\\\\\") == ("C:\\"))
     ,("W.normalise \"C:.\\\\\" == \"C:\"", property $ W.normalise "C:.\\" == "C:")
     ,("AFP_W.normalise (\"C:.\\\\\") == (\"C:\")", property $ AFP_W.normalise ("C:.\\") == ("C:"))
     ,("W.normalise \"\\\\\\\\server\\\\test\" == \"\\\\\\\\server\\\\test\"", property $ W.normalise "\\\\server\\test" == "\\\\server\\test")