How can I block a frame from being split?

Question

Currently I work with ruby and rspec. I really like the idea of having a separate frame in another monitor showing me the compilation buffer. My current setup uses a 'code' frame (in which I do actual work) and a 'test-result' frame (in which I see rspec results)

The problem is that when I try to open some compilation error or file in the 'test-result' frame, the window splits in that frame. What I would really like to do is for it to open in my 'code' frame.

I already use the option display-buffer-reuse-frames. I also tried to set the compilation results window dedicated, but whenever emacs try to open a new window, a new frame would be created (which is particularly awful if you use Helm.)

Is there some easy way to achieve this ?

Answer 1

You need to configure the 600-pound gorilla that is display-buffer-alist which determines how display-buffer chooses where to display a buffer. It makes display-buffer-reuse-frames obsolete in newer emacsen. Here is a config that should guide you (atleast in emacs 24.3).

;; all buffers, try to reuse windows across all frames
(add-to-list 'display-buffer-alist
           '(".*". (display-buffer-reuse-window .
                                  ((reusable-frames . t)))))

;; except for compilation buffers where you want new and dedicated frames when necessary
(add-to-list 'display-buffer-alist
         '("^\\*Compile-Log\\*". ((display-buffer-reuse-window
                                   display-buffer-pop-up-frame) .
                                  ((reusable-frames . t)
                                  (inhibit-same-window . t)))))

As you can see I use a regexp to match the compile-log buffer. The documentation of display-buffer should give you an idea of what is happening. Just a heads up that it is not the most enjoyable piece of documentation you will ever read. I added them sequentially so the compile-log regexp will be matched ahead of the generic regexp. Adapt the regexp to your needs.

EDIT To make any frame unsplittable you can eval M-: (set-frame-parameter nil 'unsplittable t) in that particular frame. Replace nil with required FRAME if doing it from elisp. Between these two settings, it should make the compilation frame exclusive unless you specifically find a file in that frame.