Escape ':' in file/directory names to avoid it being treated as a pathspec by some git commands

A git pathspec is a filename, except when it starts with ':', it's taken
to refer to a branch, etc. Rather than special case ':', any filename
starting with anything unusual is prefixed with "./"

This could have been a real mess to deal with, but luckily SafeCommand
is already extensively used and so we know at the type level the difference
between parameters that are files, and parameters that are command options.

Testing did show that Git.Queue was not using SafeCommand on
filenames fed to xargs. (Filenames starting with '-' worked before only
because -- was used to separate filenames from options when calling eg git
add.)

The test suite now passes with filenames starting with ':'. However, I did
not keep that change to it, because such filenames are probably not legal
on windows, and I have enough ugly windows ifdefs in there as it is.

This commit was sponsored by Otavio Salvador. Thanks!

1 files changed, 11 insertions, 5 deletions

diff --git a/Utility/SafeCommand.hs b/Utility/SafeCommand.hs
index 785aec578..d24c75dd4 100644
--- a/Utility/SafeCommand.hs
+++ b/Utility/SafeCommand.hs
@@ -1,6 +1,6 @@
 {- safely running shell commands
  -
- - Copyright 2010-2012 Joey Hess <joey@kitenet.net>
+ - Copyright 2010-2013 Joey Hess <joey@kitenet.net>
  -
  - Licensed under the GNU GPL version 3 or higher.
  -}
@@ -12,6 +12,8 @@ import Utility.Process
 import System.Process (env)
 import Data.String.Utils
 import Control.Applicative
+import System.FilePath
+import Data.Char
 
 {- A type for parameters passed to a shell command. A command can
  - be passed either some Params (multiple parameters can be included,
@@ -24,14 +26,18 @@ data CommandParam = Params String | Param String | File FilePath
 {- Used to pass a list of CommandParams to a function that runs
  - a command and expects Strings. -}
 toCommand :: [CommandParam] -> [String]
-toCommand = (>>= unwrap)
+toCommand = concatMap unwrap
   where
 	unwrap (Param s) = [s]
 	unwrap (Params s) = filter (not . null) (split " " s)
-	-- Files that start with a dash are modified to avoid
-	-- the command interpreting them as options.
-	unwrap (File s@('-':_)) = ["./" ++ s]
+	-- Files that start with a non-alphanumeric that is not a path
+	-- separator are modified to avoid the command interpreting them as
+	-- options or other special constructs.
+	unwrap (File s@(h:_))
+		| isAlphaNum h || h `elem` pathseps = [s]
+		| otherwise = ["./" ++ s]
 	unwrap (File s) = [s]
+	pathseps = [pathSeparator, '.']
 
 {- Run a system command, and returns True or False
  - if it succeeded or failed.