Using tab-bar.el with automatic tab management

Question

I want to implement automatic tab management. Every file I open needs to go into a tab. The tab into which any given buffer goes is determined by root directory of the VC repo the file belongs to.

The mechanism used by tabbar.el was tabbar-buffer-groups-function where I could use a function like

(defun my/find-vc-root ()
  "Retuns the repository root as per [vc]."
  (vc-call-backend (vc-responsible-backend default-directory)
           'root default-directory))

I do see tab-bar-new-tab-group in the code but I can't wrap my head around how it is to be used.

Answer 1

Tab groups don't create new tabs. You can implement automatic tab management at different levels, it depends on your needs.

1. If you want only C-x C-f to open a file in a new tab, then you can just rebind this key with (define-key ctl-x-map "\C-f" 'find-file-other-tab)

2. If you want every opened file to go to a new tab, this implies that you need to rely on the file-visiting hook:

(add-hook 'find-file-hook
          (lambda ()
            (let ((tab-bar-new-tab-choice (buffer-name)))
              (tab-bar-new-tab))))

3. If you want that even displaying a visited file should switch to its tab, this is possible with:

(push '((lambda (b _a) (buffer-local-value 'buffer-file-name (get-buffer b)))
        .
        (display-buffer-in-tab (tab-name . (lambda (b _a) (buffer-name b)))))
      display-buffer-alist)