make `display-buffer` open buffer in new tab

Question

The display-buffer function seems to be used quite heavily within Emacs. It has a lot of options to determine where to open a new buffer (a new window, a new frame, an existing window, etc).

Emacs introduced a concept of tabs in 27.1. However, there doesn't appear to be an easy way to tell display-buffer that you want new buffers to open in a tab, instead of just a new window.

Is there some way to configure display-buffer to open all buffers in a new (or existing?) tab?

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The solution from NickD suggests using a function like display-buffer-in-tab.

I was able to get this working by setting display-buffer-base-action like the following:

(setq display-buffer-base-action '(display-buffer-in-tab))

However, this doesn't seem to play nicely with functions like help and magit-status. They tend to open up too many tabs every time they are run.

More specific settings may be necessary per command or per new buffer.

Answer 1

There is display-buffer-in-new-tab. Its doc string says:

display-buffer-in-new-tab is a compiled Lisp function in ‘tab-bar.el’.

(display-buffer-in-new-tab BUFFER ALIST)

Display BUFFER in a new tab.
ALIST is an association list of action symbols and values.  See
Info node ‘(elisp) Buffer Display Action Alists’ for details of
such alists.

Like ‘display-buffer-in-tab’, but always creates a new tab unconditionally,
without checking if a suitable tab already exists.

If ALIST contains a ‘tab-name’ entry, it creates a new tab with that name
and displays BUFFER in a new tab.  The ‘tab-name’ entry can be a function,
then it is called with two arguments: BUFFER and ALIST, and should return
the tab name.  When a ‘tab-name’ entry is omitted, create a new tab without
an explicit name.

This is an action function for buffer display, see Info
node ‘(elisp) Buffer Display Action Functions’.  It should be
called only by ‘display-buffer’ or a function directly or
indirectly called by the latter.

Untested.

EDIT: I found this by using the Emacs help system. I don't use tab-bar-mode and I didn't know about this beforehand, but doing C-h f display-buffer-TAB shows me a completion buffer. Quickly scanning that, I found display-buffer-in-tab and display-buffer-in-new-tab. I chose the latter and got the doc string that I pasted above.

If the completion buffer is too long to scan easily by eye, you can switch to the buffer with C-x o and then just search e.g. for tab in the buffer using C-s.

Learning to use Help and also learning to search through the manuals with Info is an excellent investment of your time.