Re: master 431f8ff1e38: * lisp/imenu.el: Support more values for imenu-flatten (bug#70846)

[Juri Linkov]

>> +(defcustom completion-allow-text-properties nil
>> +  "Non-nil means `choose-completion' should not discard text properties.
>> +This also affects `completing-read' and any of the functions that do
>> +minibuffer input with completion."
>
> This new user option should be announced in NEWS.
>
> I also wonder whether it should be a user option

So here it's a variable, that will later help to select Imenu
completion candidates with same names from different groups.

diff --git a/etc/NEWS b/etc/NEWS
index 34052764f5f..0db85410ebe 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -1784,6 +1784,13 @@ A major mode based on the tree-sitter library for 
editing Lua files.
 
 ** Minibuffer and Completions
 
+*** New variable 'completion-allow-text-properties'.
+Like non-nil 'minibuffer-allow-text-properties' that doesn't discard
+text properties, it does the same by keeping text properties
+on the selected completion candidate.  So when these two variables
+both are non-nil then 'completing-read' returns a selected completion
+with the initial text properties kept intact.
+
 +++
 *** New global minor mode 'minibuffer-regexp-mode'.
 This is a minor mode for editing regular expressions in the minibuffer.
diff --git a/lisp/simple.el b/lisp/simple.el
index cdbbd876e3b..8793e590733 100644
--- a/lisp/simple.el
+++ b/lisp/simple.el
@@ -10102,6 +10102,11 @@ choose-completion-deselect-if-after
 
 This makes `completions--deselect' effective.")
 
+(defvar completion-allow-text-properties nil
+  "Non-nil means `choose-completion' should not discard text properties.
+This affects `completing-read' and any of the functions that do
+minibuffer input with completion.")
+
 (defun choose-completion (&optional event no-exit no-quit)
   "Choose the completion at point.
 If EVENT, use EVENT's position to determine the starting position.
@@ -10122,8 +10127,10 @@ choose-completion
           (completion-no-auto-exit (if no-exit t completion-no-auto-exit))
           (choice
            (if choose-completion-deselect-if-after
-               (if-let ((str (get-text-property (posn-point (event-start 
event)) 'completion--string)))
-                   (substring-no-properties str)
+               (if-let ((str (get-text-property (posn-point (event-start 
event))
+                                                'completion--string)))
+                   (if completion-allow-text-properties str
+                     (substring-no-properties str))
                  (error "No completion here"))
            (save-excursion
              (goto-char (posn-point (event-start event)))
@@ -10139,8 +10146,9 @@ choose-completion
                (setq beg (or (previous-single-property-change
                               beg 'completion--string)
                              beg))
-               (substring-no-properties
-                (get-text-property beg 'completion--string)))))))
+               (let ((str (get-text-property beg 'completion--string)))
+                 (if completion-allow-text-properties str
+                   (substring-no-properties str))))))))
 
       (unless (buffer-live-p buffer)
         (error "Destination buffer is dead"))
diff --git a/lisp/imenu.el b/lisp/imenu.el
index ea097f5da3a..952c3dc8969 100644
--- a/lisp/imenu.el
+++ b/lisp/imenu.el
@@ -732,6 +732,8 @@ imenu--completion-buffer
   ;; Create a list for this buffer only when needed.
   (let ((name (thing-at-point 'symbol))
        choice
+       (minibuffer-allow-text-properties t)
+       (completion-allow-text-properties t)
        (prepared-index-alist
         (if (not imenu-space-replacement) index-alist
           (mapcar
@@ -765,10 +767,12 @@ imenu--completion-buffer
                                  nil t nil 'imenu--history-list name)))
 
     (when (stringp name)
-      (setq choice (assoc name prepared-index-alist))
-      (if (imenu--subalist-p choice)
-         (imenu--completion-buffer (cdr choice) prompt)
-       choice))))
+      (or (get-text-property 0 'imenu-choice name)
+         (progn
+           (setq choice (assoc name prepared-index-alist))
+           (if (imenu--subalist-p choice)
+               (imenu--completion-buffer (cdr choice) prompt)
+             choice))))))
 
 (defun imenu--mouse-menu (index-alist event &optional title)
   "Let the user select from a buffer index from a mouse menu.
@@ -803,7 +807,8 @@ imenu--flatten-index-alist
        ((not (imenu--subalist-p item))
         (list (cons (if (and (eq imenu-flatten 'annotation) prefix)
                         (propertize name 'imenu-section
-                                    (format " (%s)" prefix))
+                                    (format " (%s)" prefix)
+                                    'imenu-choice item)
                       new-prefix)
                     pos)))
        (t