airblade/vim-gitgutter — pull request #22 by theaeolianmachine (2013-03-05 23:45:32+00:00)
Title: Add FAQ note for git diff color settings.

I found that my git config had color.diff = always, and this caused the
grep command (grep -e "^@@ "') to return no matches when diffing
the file in s:run_diff().