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

[Juri Linkov <juri@linkov.net>]

> I forgot to mention that this also affects using previous minibuffer
> inputs with M-p: the text properties aren't recorded in the history
> list, so you get an ambiguous input that doesn't always take you to
> where you went when you previously used that input.

Do you mean that text properties are not saved between sessions?
Because in the same session text properties are preserved in the history.
(This assumes that you select candidates by completion selection UI.)

>> Unfortunately, that'd be a step back.  Maybe at least we could document
>> limitations that annotations work only by selection.
>
> Indeed my suggestion was to take a step back of sorts.  If it's too late
> for that, I agree it's a good idea to document the known issues.

Ok, so here is a patch for emacs-30:

diff --git a/lisp/imenu.el b/lisp/imenu.el
index 708a39a0f71..ae030e0104a 100644
--- a/lisp/imenu.el
+++ b/lisp/imenu.el
@@ -158,6 +158,9 @@ imenu-flatten
 with a suffix that is the section name to which it belongs.
 If the value is `group', split completion candidates into groups
 according to the sections.
+Since the values `annotation' and `group' rely on text properties,
+you can use them only by selecting candidates from the completions
+buffer, not by typing in the minibuffer.
 Any other value is treated as `prefix'.

>> It can't be boolean, because a more reliable replacement for annotations
>> would be appending the suffix, i.e. by the new value 'suffix'.
>
> That makes sense.

Ok, here is the implementation for emacs-30 where documentation could be
added later to not cause merge conflicts with the documentation changes above:

diff --git a/lisp/imenu.el b/lisp/imenu.el
index 708a39a0f71..31937d3f333 100644
--- a/lisp/imenu.el
+++ b/lisp/imenu.el
@@ -827,6 +830,9 @@ imenu--flatten-index-alist
                        ('group (propertize name
                                            'imenu-section (or prefix "*")
                                            'imenu-choice item))
+                       ('suffix (if prefix
+				    (concat name imenu-level-separator prefix)
+			          name))
                        (_ new-prefix))
 		     pos)))