By default if you use fugitive.vim's :Gdiff on a file buffer which is in conflict with git, you will get a three way diff showing HEAD, the working copy (with conflict markers), and the merge.
I like to have git config merge.conflictstyle diff3 set, which includes the base (most recent common ancestor of HEAD and merge in the conflict markers.
Unfortunately even with diff3 as the conflictstyle in fugitive.vim you still only get 3 panes (no base).
Does anyone know how to make show it in another pane? Ideally about the working copy.
This comment from Tim Pope seems to provide some clue, but I can't quite figure it out.
You can do it with the following steps:
:split - Do a horizontal split:Gdiff - Diff in the top windowGedit :1 - Load ancestor in bottom windowGedit :2 loads head and Gedit :3 loads the merge