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

[Juri Linkov]

> One way to disambiguate them is to use text properties
> on the completion candidate strings.
>
> But unfortunately read-from-minibuffer doesn't obey
> a non-nil value of minibuffer-allow-text-properties,
> because choose-completion unconditionally discards all properties
> by substring-no-properties.
>
> Maybe choose-completion should use substring instead of
> substring-no-properties when minibuffer-allow-text-properties
> is non-nil?

Here is a new variable that helps to disambiguate completions with
the same name but different annotations by using text properties:

diff --git a/lisp/imenu.el b/lisp/imenu.el
index 93a544ff550..af344e5e250 100644
--- a/lisp/imenu.el
+++ b/lisp/imenu.el
@@ -729,6 +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
@@ -762,10 +768,12 @@ 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.
@@ -800,7 +808,8 @@ 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
diff --git a/lisp/simple.el b/lisp/simple.el
index deab52c4201..fa180323963 100644
--- a/lisp/simple.el
+++ b/lisp/simple.el
@@ -10102,6 +10102,14 @@ choose-completion-deselect-if-after
 
 This makes `completions--deselect' effective.")
 
+(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."
+  :type 'boolean
+  :version "30.1"
+  :group '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.
@@ -10123,7 +10131,9 @@ choose-completion
           (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 completion-allow-text-properties
+                       (substring str)
+                     (substring-no-properties str))
                  (error "No completion here"))
            (save-excursion
              (goto-char (posn-point (event-start event)))
@@ -10139,8 +10149,11 @@ choose-completion
                (setq beg (or (previous-single-property-change
                               beg 'completion--string)
                              beg))
-               (substring-no-properties
-                (get-text-property beg 'completion--string)))))))
+               (if completion-allow-text-properties
+                   (substring
+                    (get-text-property beg 'completion--string))
+                 (substring-no-properties
+                  (get-text-property beg 'completion--string))))))))
 
       (unless (buffer-live-p buffer)
         (error "Destination buffer is dead"))