From a99d0e7e6c903e0e1cb32a458802c1d8d7443cd9 Mon Sep 17 00:00:00 2001
From: Juri Linkov <juri@linkov.net>
Date: Tue, 13 Dec 2022 19:47:47 +0200
Subject: [PATCH] Support a function in the BUFFER-LIST arg of
 list-buffers-noselect (bug#59935)

* lisp/buff-menu.el (Buffer-menu-buffer-list): New buffer-local variable.
(list-buffers-noselect): Set Buffer-menu-buffer-list to 'buffer-list'
that now keeps the buffer-local value of the provided buffer list
or a function that returns the buffer list.
(list-buffers--refresh): Handle buffer-list and Buffer-menu-buffer-list
as a function and as a list.

* lisp/progmodes/project.el (project-list-buffers): Let-bind
'buffer-list-function' used by both legacy code and the new version
of list-buffers-noselect that supports its arg BUFFER-LIST as a function.
---
 lisp/buff-menu.el         | 23 ++++++++++++++++++-----
 lisp/progmodes/project.el | 25 ++++++++++++++++++++-----
 2 files changed, 38 insertions(+), 10 deletions(-)

diff --git a/lisp/buff-menu.el b/lisp/buff-menu.el
index 588fe599a46..448a5395c04 100644
--- a/lisp/buff-menu.el
+++ b/lisp/buff-menu.el
@@ -107,6 +107,9 @@ The value should be a function of one argument; it will be
 called with the buffer.  If this function returns non-nil,
 then the buffer will be displayed in the buffer list.")
 
+(defvar-local Buffer-menu-buffer-list nil
+  "The current list of buffers or function to return buffers.")
+
 (defvar-keymap Buffer-menu-mode-map
   :doc "Local keymap for `Buffer-menu-mode' buffers."
   :parent tabulated-list-mode-map
@@ -628,8 +631,10 @@ This behaves like invoking \\[read-only-mode] in that buffer."
 This is called by `buffer-menu' and others as a subroutine.
 
 If FILES-ONLY is non-nil, show only file-visiting buffers.
-If BUFFER-LIST is non-nil, it should be a list of buffers; it
-means list those buffers and no others.
+If BUFFER-LIST is non-nil, it should be either a list of buffers
+or a function that returns a list of buffers; it means
+list those buffers and no others.
+See more at `Buffer-menu-buffer-list'.
 If FILTER-PREDICATE is non-nil, it should be a function
 that filters out buffers from the list of buffers.
 See more at `Buffer-menu-filter-predicate'."
@@ -639,6 +644,7 @@ See more at `Buffer-menu-filter-predicate'."
       (Buffer-menu-mode)
       (setq Buffer-menu-files-only
 	    (and files-only (>= (prefix-numeric-value files-only) 0)))
+      (setq Buffer-menu-buffer-list buffer-list)
       (setq Buffer-menu-filter-predicate filter-predicate)
       (list-buffers--refresh buffer-list old-buffer)
       (tabulated-list-print))
@@ -665,9 +671,16 @@ See more at `Buffer-menu-filter-predicate'."
 			       Buffer-menu-filter-predicate))
 	entries name-width)
     ;; Collect info for each buffer we're interested in.
-    (dolist (buffer (or buffer-list
-			(buffer-list (if Buffer-menu-use-frame-buffer-list
-					 (selected-frame)))))
+    (dolist (buffer (cond
+                     ((functionp buffer-list)
+                      (funcall buffer-list))
+                     (buffer-list)
+                     ((functionp Buffer-menu-buffer-list)
+                      (funcall Buffer-menu-buffer-list))
+                     (Buffer-menu-buffer-list)
+                     (t (buffer-list
+                         (if Buffer-menu-use-frame-buffer-list
+                             (selected-frame))))))
       (with-current-buffer buffer
 	(let* ((name (buffer-name))
 	       (file buffer-file-name))
diff --git a/lisp/progmodes/project.el b/lisp/progmodes/project.el
index 7cdaba9c07d..4fd855255b0 100644
--- a/lisp/progmodes/project.el
+++ b/lisp/progmodes/project.el
@@ -1340,18 +1340,33 @@ By default, all project buffers are listed except those whose names
 start with a space (which are for internal use).  With prefix argument
 ARG, show only buffers that are visiting files."
   (interactive "P")
-  (let ((pr (project-current t)))
+  (let* ((pr (project-current t))
+         (buffer-list-function
+          (lambda ()
+            (seq-filter
+             (lambda (buffer)
+               (let ((name (buffer-name buffer))
+                     (file (buffer-file-name buffer)))
+                 (and (or (not (string= (substring name 0 1) " "))
+                          file)
+                      (not (eq buffer (current-buffer)))
+                      (or file (not Buffer-menu-files-only)))))
+             (project-buffers pr)))))
     (display-buffer
      (if (version< emacs-version "29.0.50")
-         (let ((buf (list-buffers-noselect arg (project-buffers pr))))
+         (let ((buf (list-buffers-noselect
+                     arg (with-current-buffer
+                             (get-buffer-create "*Buffer List*")
+                           (let ((Buffer-menu-files-only arg))
+                             (funcall buffer-list-function))))))
            (with-current-buffer buf
              (setq-local revert-buffer-function
                          (lambda (&rest _ignored)
-                           (list-buffers--refresh (project-buffers pr))
+                           (list-buffers--refresh
+                            (funcall buffer-list-function))
                            (tabulated-list-print t))))
            buf)
-       (list-buffers-noselect
-        arg nil (lambda (buf) (memq buf (project-buffers pr))))))))
+       (list-buffers-noselect arg buffer-list-function)))))
 
 (defcustom project-kill-buffer-conditions
   '(buffer-file-name    ; All file-visiting buffers are included.
-- 
2.39.2