Allow plugin to bypass any alias for grep.

This is an opt-in configuration.

README.mkd

@@ -77,6 +77,7 @@ You can customise:
 * The signs' colours and symbols
 * Line highlights
 * Extra arguments for `git diff`
+* Whether or not to escape `grep` (default to no)
 * Whether or not vim-gitgutter is on initially (defaults to on)
 * Whether or not signs are shown (defaults to yes)
 * Whether or not line highlighting is on initially (defaults to off)
@@ -152,6 +153,14 @@ If you want to pass extra arguments to `git diff`, for example to ignore whitesp
 let g:gitgutter_diff_args = '-w'
 ```
 
+#### Whether or not to escape `grep`
+
+If you have `grep` aliased to something which changes its output, for example `grep --color=auto -H`, you will need to tell vim-gitgutter to use raw grep:
+
+```viml
+let g:gitgutter_escape_grep = 1
+```
+
 #### To turn off vim-gitgutter by default
 
 Add `let g:gitgutter_enabled = 0` to your `~/.vimrc`.
@@ -218,7 +227,6 @@ Here are some things you can check:
 * Your git config is compatible with the version of git which your Vim is calling (`:echo system('git --version')`).
 * Your Vim supports signs (`:echo has('signs')` should give `1`).
 * Your file is being tracked by git and has unstaged changes.
-* `grep` is on your path and available to Vim (`:echo executable('grep')` should return 1)
 
 
 ### Alternatives

doc/gitgutter.txt

@@ -95,6 +95,7 @@ You can customise:
 - The signs' colours and symbols
 - Line highlights
 - Extra arguments for git-diff
+- Whether or not to escape grep (defaults to no)
 - Whether or not vim-gitgutter is on initially (defaults to on)
 - Whether or not signs are shown (defaults to yes)
 - Whether or not line highlighting is on initially (defaults to off)
@@ -181,6 +182,13 @@ To pass extra arguments to git-diff, add this to your |vimrc|:
   let g:gitgutter_diff_args = '-w'
 <
 
+TO ESCAPE GREP
+
+To avoid any alias you have for grep, use this:
+>
+  let g:gitgutter_escape_grep = 1
+<
+
 TO TURN OFF VIM-GITGUTTER BY DEFAULT
 
 Add to your |vimrc|

plugin/gitgutter.vim

@@ -27,6 +27,7 @@ call s:set('g:gitgutter_sign_modified',         '~')
 call s:set('g:gitgutter_sign_removed',          '_')
 call s:set('g:gitgutter_sign_modified_removed', '~_')
 call s:set('g:gitgutter_diff_args',             '')
+call s:set('g:gitgutter_escape_grep',           0)
 
 let s:file = ''
 
@@ -48,6 +49,7 @@ function! s:init()
     let s:dummy_sign_id = 153
 
     let s:grep_available = executable('grep')
+    let s:grep_command = ' | ' . (g:gitgutter_escape_grep ? '\grep' : 'grep') . ' -e "^@@ "'
 
     let g:gitgutter_initialised = 1
   endif
@@ -193,7 +195,7 @@ endfunction
 function! s:run_diff()
   let cmd = 'git diff --no-ext-diff --no-color -U0 ' . g:gitgutter_diff_args . ' ' . shellescape(s:file())
   if s:grep_available
-    let cmd .= ' | grep -e "^@@ "'
+    let cmd .= s:grep_command
   endif
   let diff = system(s:command_in_directory_of_file(cmd))
   return diff