Can ediff merge simultaneously show the ancestor, A, B, and merge buffers?
diff, emacs, emacs-ediff, kdiff3, merge
Solution
This has being added to the trunk version. Now by default, 3-way merges show four buffers, i.e., "local" (buffer A), "remote" (buffer B), the merge result (buffer C) and the ancestor. You can change this default customizing the new option 'ediff-show-ancestor'.
The key '/' is now bound to a new command 'ediff-toggle-show-ancestor': it toggles whether to show 3 (local, remote and result) or 4 (local, remote, result, ancestor) buffers.
These changes will be visible in Emacs 26.1 release.
Problem
I'm a die-hard `emacs` user, but so far have always used `kdiff3` for 3-way merges with ancestor, e.g. when performing `git merge` or `rebase`. I really like the way that `kdiff3` can not only simultaneously display all four versions of the text being merged: - the common ancestor (buffer A in `kdiff3`) - "ours" a.k.a. "local" (buffer B in `kdiff3`) - "theirs" a.k.a. "remote" (buffer C in `kdiff3`) - the merge result or target but also makes the differences between A, B, and C clear via colour highlighting. However, `kdiff3` unsurprisingly sucks in comparison to `emacs` when it comes to text editing of the merge buffer, since `kdiff3` is not a full-blown text editor. It also doesn't integrate out of the box with the excellent `magit` package. So I'm trying to switch to using `ediff` when resolving conflicts in this particular scenario (I have been successfully using `ediff` for other use cases for many years). However, despite reading the `ediff` manual and EmacsWiki page, and asking on `#emacs` IRC, I can't find a way to simultaneously display all 4 buffers. By default it shows: - "ours" a.k.a. "local" (labelled buffer A) - "theirs" a.k.a. "remote" (labelled buffer B) - the merge result or target (labelled buffer C) Pressing `/` switches the window displaying the merge result buffer (C) so that it displays the ancestor buffer, but you can't see the ancestor and the merge result simultaneously. (Also, the diff in the ancestor buffer is highlighted in a single colour which doesn't clearly show which bits differ from the other two visible buffers (A and B), although according to this thread, it seems that unfortunately ancestor diff refinement hasn't been implemented yet.) Is there an easy way to configure `ediff` to simultaneously display all 4 buffers?