* lisp/window.el (switch-to-buffer-obey-display-actions): New defcustom.

(switch-to-buffer): Use it.  (Bug#32790)
(switch-to-buffer-preserve-window-point):  Mention it in docstring.

* lisp/windmove.el (windmove-display-in-direction): Mention it in docstring.

* doc/lispref/windows.texi (Switching Buffers):
Document switch-to-buffer-obey-display-actions.

4 files changed, 86 insertions, 36 deletions

diff --git a/doc/lispref/windows.texi b/doc/lispref/windows.texi
index eb057662112..f2f6cd3a42a 100644
--- a/doc/lispref/windows.texi
+++ b/doc/lispref/windows.texi
@@ -2263,6 +2263,12 @@ selected window or never appeared in it before, or if
 buffer.
 @end defopt
 
+@defopt switch-to-buffer-obey-display-actions
+If this variable is non-@code{nil}, @code{switch-to-buffer} respects
+display actions specified by @code{display-buffer-overriding-action},
+@code{display-buffer-alist} and other display related variables.
+@end defopt
+
 The next two commands are similar to @code{switch-to-buffer}, except for
 the described features.
 
diff --git a/etc/NEWS b/etc/NEWS
index 7ff4aee64b5..7a2123a2128 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -243,6 +243,12 @@ when the last screen line in a window is not fully visible.
 ** New variable 'emacs-repository-branch'.
 It reports the git branch from which Emacs was built.
 
++++
+** New user option 'switch-to-buffer-obey-display-actions'.
+When non-nil, `switch-to-buffer' uses `pop-to-buffer-same-window' that
+respects display actions specified by `display-buffer-alist' and
+`display-buffer-overriding-action'.
+
 
 * Editing Changes in Emacs 27.1
 
diff --git a/lisp/windmove.el b/lisp/windmove.el
index 6d61806a831..c16c12444a0 100644
--- a/lisp/windmove.el
+++ b/lisp/windmove.el
@@ -588,7 +588,9 @@ By default, select the window with a displayed buffer.
 If prefix ARG is `C-u', reselect a previously selected window.
 If `windmove-display-no-select' is non-nil, this command doesn't
 select the window with a displayed buffer, and the meaning of
-the prefix argument is reversed."
+the prefix argument is reversed.
+When `switch-to-buffer-obey-display-actions' is non-nil,
+`switch-to-buffer' commands are also supported."
   (let* ((no-select (not (eq (consp arg) windmove-display-no-select))) ; xor
          (old-window (or (minibuffer-selected-window) (selected-window)))
          (new-window)
diff --git a/lisp/window.el b/lisp/window.el
index a52b8951b15..50aec86a427 100644
--- a/lisp/window.el
+++ b/lisp/window.el
@@ -7768,7 +7768,9 @@ position in the selected window.
 
 This variable is ignored if the buffer is already displayed in
 the selected window or never appeared in it before, or if
-`switch-to-buffer' calls `pop-to-buffer' to display the buffer."
+`switch-to-buffer' calls `pop-to-buffer' to display the buffer,
+or non-nil `switch-to-buffer-obey-display-actions' displays it
+in another window."
   :type '(choice
           (const :tag "Never" nil)
           (const :tag "If already displayed elsewhere" already-displayed)
@@ -7803,6 +7805,16 @@ FORCE-SAME-WINDOW is non-nil."
   :group 'windows
   :version "25.1")
 
+(defcustom switch-to-buffer-obey-display-actions nil
+  "If non-nil, `switch-to-buffer' runs `pop-to-buffer-same-window' instead.
+This means that when switching the buffer it respects display actions
+specified by `display-buffer-overriding-action', `display-buffer-alist'
+and other display related variables.  So `switch-to-buffer' will display
+the buffer in the window specified by the rules from these variables."
+  :type 'boolean
+  :group 'windows
+  :version "27.1")
+
 (defun switch-to-buffer (buffer-or-name &optional norecord force-same-window)
   "Display buffer BUFFER-OR-NAME in the selected window.
 
@@ -7835,59 +7847,83 @@ displaying it the most recently selected one.
 If optional argument FORCE-SAME-WINDOW is non-nil, the buffer
 must be displayed in the selected window when called
 non-interactively; if that is impossible, signal an error rather
-than calling `pop-to-buffer'.
+than calling `pop-to-buffer'.  It has no effect when the option
+`switch-to-buffer-obey-display-actions' is non-nil.
 
 The option `switch-to-buffer-preserve-window-point' can be used
 to make the buffer appear at its last position in the selected
 window.
 
+If the option `switch-to-buffer-obey-display-actions' is non-nil,
+run the function `pop-to-buffer-same-window' instead.
+This may display the buffer in another window as specified by
+`display-buffer-overriding-action', `display-buffer-alist' and
+other display related variables.  If this results in displaying
+the buffer in the selected window, window start and point are adjusted
+as prescribed by the option `switch-to-buffer-preserve-window-point'.
+Otherwise, these are left alone.
+
 Return the buffer switched to."
   (interactive
    (let ((force-same-window
-          (cond
-           ((window-minibuffer-p) nil)
-           ((not (eq (window-dedicated-p) t)) 'force-same-window)
-           ((pcase switch-to-buffer-in-dedicated-window
-              ('nil (user-error
-                     "Cannot switch buffers in a dedicated window"))
-              ('prompt
-               (if (y-or-n-p
-                    (format "Window is dedicated to %s; undedicate it"
-                            (window-buffer)))
-                   (progn
-                     (set-window-dedicated-p nil nil)
-                     'force-same-window)
-                 (user-error
-                  "Cannot switch buffers in a dedicated window")))
-              ('pop nil)
-              (_ (set-window-dedicated-p nil nil) 'force-same-window))))))
+          (unless switch-to-buffer-obey-display-actions
+            (cond
+             ((window-minibuffer-p) nil)
+             ((not (eq (window-dedicated-p) t)) 'force-same-window)
+             ((pcase switch-to-buffer-in-dedicated-window
+                ('nil (user-error
+                       "Cannot switch buffers in a dedicated window"))
+                ('prompt
+                 (if (y-or-n-p
+                      (format "Window is dedicated to %s; undedicate it"
+                              (window-buffer)))
+                     (progn
+                       (set-window-dedicated-p nil nil)
+                       'force-same-window)
+                   (user-error
+                    "Cannot switch buffers in a dedicated window")))
+                ('pop nil)
+                (_ (set-window-dedicated-p nil nil) 'force-same-window)))))))
      (list (read-buffer-to-switch "Switch to buffer: ") nil force-same-window)))
-  (let ((buffer (window-normalize-buffer-to-switch-to buffer-or-name)))
+  (let ((buffer (window-normalize-buffer-to-switch-to buffer-or-name))
+        (set-window-start-and-point (not switch-to-buffer-obey-display-actions)))
     (cond
      ;; Don't call set-window-buffer if it's not needed since it
      ;; might signal an error (e.g. if the window is dedicated).
-     ((eq buffer (window-buffer)))
-     ((window-minibuffer-p)
+     ((and (eq buffer (window-buffer))
+           ;; pop-to-buffer-same-window might decide to display
+           ;; the same buffer in another window
+           (not switch-to-buffer-obey-display-actions)))
+     ((and (window-minibuffer-p)
+           (not switch-to-buffer-obey-display-actions))
       (if force-same-window
           (user-error "Cannot switch buffers in minibuffer window")
         (pop-to-buffer buffer norecord)))
-     ((eq (window-dedicated-p) t)
+     ((and (eq (window-dedicated-p) t)
+           (not switch-to-buffer-obey-display-actions))
       (if force-same-window
           (user-error "Cannot switch buffers in a dedicated window")
         (pop-to-buffer buffer norecord)))
      (t
-      (let* ((entry (assq buffer (window-prev-buffers)))
-             (displayed (and (eq switch-to-buffer-preserve-window-point
-                                 'already-displayed)
-                             (get-buffer-window buffer 0))))
-        (set-window-buffer nil buffer)
-        (when (and entry
-                   (or (eq switch-to-buffer-preserve-window-point t)
-                       displayed))
-          ;; Try to restore start and point of buffer in the selected
-          ;; window (Bug#4041).
-          (set-window-start (selected-window) (nth 1 entry) t)
-          (set-window-point nil (nth 2 entry))))))
+      (when switch-to-buffer-obey-display-actions
+        (let ((selected-window (selected-window)))
+          (pop-to-buffer-same-window buffer norecord)
+          (when (eq (selected-window) selected-window)
+            (setq set-window-start-and-point t))))
+
+      (when set-window-start-and-point
+        (let* ((entry (assq buffer (window-prev-buffers)))
+               (displayed (and (eq switch-to-buffer-preserve-window-point
+                                   'already-displayed)
+                               (get-buffer-window buffer 0))))
+          (set-window-buffer nil buffer)
+          (when (and entry
+                     (or (eq switch-to-buffer-preserve-window-point t)
+                         displayed))
+            ;; Try to restore start and point of buffer in the selected
+            ;; window (Bug#4041).
+            (set-window-start (selected-window) (nth 1 entry) t)
+            (set-window-point nil (nth 2 entry)))))))
 
     (unless norecord
       (select-window (selected-window)))