Export a Git diff command
GV current shows various Git diffs (unlike vim-fugitive, whichonly shows database objects), so it makes sense to export this functionality, say, for viewing the diff against HEAD or the index.
For instance:
:call gv#diff("HEAD")
:call gv#diff("--cached", "HEAD")
Doesn't fugitive already provide this? :Gdiff ... for the current file or :Git diff ... for the whole repo.
Yes, the vimdiff-based Gdiff works with vim-fugitive, however sometimes I just want a quick glance at the unidiff-based format of the diff in a split window, which is what gv good at.
Did you try :Git diff ... (not :Gdiff) ?
Yes, however that halts Vim to spawn Git. I think the gv diff buffer in a split window has some benefits over it.