master 664f160297f: New value 'with-completions-popup' of 'icomplete-in-buffer' (bug#81537)

branch: master
commit 664f160297f97307669015ea56befc1ed2558ea9
Author: Juri Linkov <[email protected]>
Commit: Juri Linkov <[email protected]>

    New value 'with-completions-popup' of 'icomplete-in-buffer' (bug#81537)
    
    * etc/NEWS: Announce the change.
    
    * lisp/minibuffer.el (completion--icomplete-in-buffer-p):
    Remove function.
    (completion-list-inhibit-functions): New variable.
    (completion-list-inhibit-p): New function.
    (completion--do-completion, completion--in-region-1): Replace
    'completion--icomplete-in-buffer-p' with
    'completion-list-inhibit-p'.
    
    * lisp/icomplete.el (icomplete-in-buffer):
    Add new value 'with-completions-popup'.
    (icomplete-list-inhibit): New function.
    (icomplete--in-region-setup): Add/remove
    'icomplete-list-inhibit' from/to
    'completion-list-inhibit-functions'.
---
 etc/NEWS           |  2 ++
 lisp/icomplete.el  | 18 +++++++++++++++---
 lisp/minibuffer.el | 18 ++++++++++++------
 3 files changed, 29 insertions(+), 9 deletions(-)

diff --git a/etc/NEWS b/etc/NEWS
index 232eb6a6ca2..d9c30749ab4 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -106,6 +106,8 @@ Therefore, the instructions in the NEWS file for Emacs 30.1 to add
     (advice-add 'completion-at-point :after #'minibuffer-hide-completions)
 
 to your initialization file no longer apply, and you may remove it.
+If you still want to show the "*Completions*" buffer, then customize
+the user option 'icomplete-in-buffer' to the value 'with-completions-popup'.
 
 
 * Editing Changes in Emacs 32.1
diff --git a/lisp/icomplete.el b/lisp/icomplete.el
index c8da0e9bf9b..8902cb2354e 100644
--- a/lisp/icomplete.el
+++ b/lisp/icomplete.el
@@ -154,8 +154,11 @@ See `icomplete-delay-completions-threshold'."
 (defcustom icomplete-in-buffer nil
   "If non-nil, use Icomplete when completing in buffers other than minibuffer.
 This affects commands like `completion-in-region', but not commands
-that use their own completions setup."
-  :type 'boolean)
+that use their own completions setup.  If the value is `with-completions-popup',
+display both in-buffer completions and the *Completions* buffer."
+  :type '(choice (const :tag "Disable" nil)
+                 (const :tag "Enable" t)
+                 (const :tag "Enable with popup window" with-completions-popup)))
 
 (defcustom icomplete-minibuffer-setup-hook nil
   "Icomplete-specific customization of minibuffer setup.
@@ -621,6 +624,11 @@ Usually run by inclusion in `minibuffer-setup-hook'."
 
 (defvar icomplete--in-region-buffer nil)
 
+(defun icomplete-list-inhibit ()
+  "Decide whether to inhibit the display of the *Completions* buffer."
+  (and (not (eq icomplete-in-buffer 'with-completions-popup))
+       (eq icomplete--in-region-buffer (current-buffer))))
+
 (defun icomplete--in-region-setup ()
   (when (or (not completion-in-region-mode)
 	    (and icomplete--in-region-buffer
@@ -629,6 +637,8 @@ Usually run by inclusion in `minibuffer-setup-hook'."
       (setq icomplete--in-region-buffer nil)
       (delete-overlay icomplete-overlay)
       (kill-local-variable 'completion-show-inline-help)
+      (remove-hook 'completion-list-inhibit-functions
+                   #'icomplete-list-inhibit t)
       (remove-hook 'post-command-hook #'icomplete-post-command-hook t)
       (message nil)))
   (when (and completion-in-region-mode
@@ -640,7 +650,9 @@ Usually run by inclusion in `minibuffer-setup-hook'."
       (unless (memq icomplete-minibuffer-map (cdr tem))
 	(setcdr tem (make-composed-keymap icomplete-minibuffer-map
 					  (cdr tem)))))
-    (add-hook 'post-command-hook #'icomplete-post-command-hook nil t)))
+    (add-hook 'post-command-hook #'icomplete-post-command-hook nil t)
+    (add-hook 'completion-list-inhibit-functions
+              #'icomplete-list-inhibit nil t)))
 
 (defun icomplete--sorted-completions ()
   (or completion-all-sorted-completions
diff --git a/lisp/minibuffer.el b/lisp/minibuffer.el
index 4da651cc450..919e257ef7a 100644
--- a/lisp/minibuffer.el
+++ b/lisp/minibuffer.el
@@ -1581,8 +1581,14 @@ Calls `completion-boundaries' with STRING, COLLECTION, PRED, SUFFIX."
          (end (+ (length string) (cdr boundaries))))
     (>= start pos end)))
 
-(defun completion--icomplete-in-buffer-p ()
-  (eq (bound-and-true-p icomplete--in-region-buffer) (current-buffer)))
+(defvar completion-list-inhibit-functions nil
+  "Abnormal hook for inhibiting display of the *Completions* buffer.
+If any of these functions returns non-nil, it inhibits the display
+of *Completions*.")
+
+(defun completion-list-inhibit-p ()
+  "Return non-nil to inhibit the display of the *Completions* buffer."
+  (run-hook-with-args-until-success 'completion-list-inhibit-functions))
 
 (defun completion--do-completion (beg end &optional
                                       try-completion-function expect-exact)
@@ -1689,7 +1695,7 @@ when the buffer's text is already an exact match."
               (minibuffer-force-complete beg end))
              ((or completed only-changed-boundaries)
               (cond
-               ((completion--icomplete-in-buffer-p)) ; Bug#81537.
+               ((completion-list-inhibit-p)) ; Bug#81537.
                ((pcase completion-auto-help
                   ('visible (minibuffer--completions-visible))
                   ('always t))
@@ -1704,7 +1710,7 @@ when the buffer's text is already an exact match."
              ;; Show the completion table, if requested.
              ((not exact)
 	      (if (if (or (eq completion-auto-help 'lazy)
-                          (completion--icomplete-in-buffer-p)) ; Bug#81537.
+                          (completion-list-inhibit-p)) ; Bug#81537.
                       (eq this-command last-command)
                     completion-auto-help)
                   (minibuffer-completion-help beg end)
@@ -1712,7 +1718,7 @@ when the buffer's text is already an exact match."
              ;; If the last exact completion and this one were the same, it
              ;; means we've already given a "Complete, but not unique" message
              ;; and the user's hit TAB again, so now we give him help
-             ;; (even if `completion--icomplete-in-buffer-p' is non-nil).
+             ;; (even if `completion-list-inhibit-p' returns non-nil).
              (t
               (when (and (eq this-command last-command) completion-auto-help)
                 (minibuffer-completion-help beg end))
@@ -1785,7 +1791,7 @@ scroll the window of possible completions."
         ;; for them because Icomplete users probably expect to have to
         ;; C-g out of completion before using other bindings, but maybe
         ;; we can still fix it.  --spwhitton
-        (unless (completion--icomplete-in-buffer-p)
+        (unless (completion-list-inhibit-p)
           (if (window-live-p minibuffer-scroll-window)
               (and (eq completion-auto-select t)
                    (eq t (frame-visible-p (window-frame minibuffer-scroll-window)))