[GHC] #2184: if findExecutable finds a file that matchs the argument don't check if it is an executable

[GHC]

#2184: if findExecutable finds a file that matchs the argument don't check if it
is an executable
------------------------------------------------+---------------------------
    Reporter:  iago                             |       Owner:                     
        Type:  bug                              |      Status:  new                
    Priority:  normal                           |   Component:  libraries/directory
     Version:  6.8.2                            |    Severity:  normal             
    Keywords:  findExecutable check executable  |    Testcase:                     
Architecture:  x86                              |          Os:  Linux              
------------------------------------------------+---------------------------
 When search finds a file that matchs with the fileName argument of
 findExecutable, it doesn't check if the file is an executable file.

 {{{
  do
   path <- getEnv "PATH"
   search (splitSearchPath path)
   where
     fileName = binary <.> exeExtension

     search :: [FilePath] -> IO (Maybe FilePath)
     search [] = return Nothing
     search (d:ds) = do
         let path = d </> fileName
         b <- doesFileExist path
         if b then return (Just path)
              else search ds
 }}}

 findExecutable mustn't returns a file that it isn't an executable file,
 for example

 (~/bin is in PATH variable)
 {{{
 $ touch ~/bin/foofile
 $ ghci
 $ :m System.Directory
 $ findExecutable "foofile"
 }}}

 shows that findExecutable returns IO (Just "/home/iago/bin/foofile").

 Altought is not a bug, could be good add a new funcion (findExecutables
 for example) to return all the executables in all the paths of PATH
 variable that matchs with a given filename (like which -a).

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/2184>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler