bug#9199: Imenu does not work any more with C/C++ mode

bug#9199: Imenu does not work any more with C/C++ mode

[Angelo Graziosi]

$ cat init.el
(add-hook 'c-mode-hook
           '(lambda()
              (imenu-add-to-menubar "Functions")
              )
           )


$ cat test.c
int main(){}
void foo1(){}
void foo2(){}
void foo2(){}

$ emacs test.c &

Now click on 'Functions' in the menu bar, the result is as in

https://lists.gnu.org/archive/html/emacs-devel/2011-07/jpgDDUvliLSqM.jpg

the drop-down menu is very very compressed. The same occurs with c-mode 
--> c++-mode.

If I remove init.el completely and

$ emacs test.c &
M-x imenu-add-to-menubar <RET>
Functions <RET>

Now clicking on Functions works as expected!

If in the above init.el file I change c-mode with f90, fortran, sh... it 
works right.

The last trunk I can test and with which it works with C/C++, is rev. 
104859 (july 1 or 2).


Ciao,
   Angelo.

bug#9199: Imenu does not work any more with C/C++ mode

[Stefan Monnier]

> $ cat init.el
> (add-hook 'c-mode-hook
>           '(lambda()
>              (imenu-add-to-menubar "Functions")
>              )
>           )

Running for the Useless Use of Quote Award? ;-)

> $ cat test.c
> int main(){}
> void foo1(){}
> void foo2(){}
> void foo2(){}
> $ emacs test.c &
> Now click on 'Functions' in the menu bar, the result is as in

Hmm... indeed.

> If I remove init.el completely and
> $ emacs test.c &
> M-x imenu-add-to-menubar <RET>
> Functions <RET>
> Now clicking on Functions works as expected!

Yup: the reason why this (and other major modes) works is that the bug
only manifests itself if you call imenu-add-to-menubar more than once
(and it so happens that c-mode-hook is run twice for some reason).

I believe this is fixed in the trunk now thanks the the patch below,


        Stefan


=== modified file 'lisp/ChangeLog'
--- lisp/ChangeLog	2012-03-13 23:27:56 +0000
+++ lisp/ChangeLog	2012-03-15 01:37:45 +0000
@@ -1,3 +1,9 @@
+2012-03-15  Stefan Monnier  <monnier@iro.umontreal.ca>
+
+	* imenu.el: Fix multiple inheritance breakage (bug#9199).
+	(imenu-add-to-menubar): Don't add a redundant index.
+	(imenu-update-menubar): Handle a dynamically composed keymap.
+
 2012-03-13  Katsumi Yamaoka  <yamaoka@jpl.org>
 
 	* mail/sendmail.el (mail-encode-header):

=== modified file 'lisp/imenu.el'
--- lisp/imenu.el	2012-01-19 07:21:25 +0000
+++ lisp/imenu.el	2012-03-15 01:32:35 +0000
@@ -963,13 +963,14 @@
 	  imenu-generic-expression
 	  (not (eq imenu-create-index-function
 		   'imenu-default-create-index-function)))
+      (unless (keymapp (lookup-key (current-local-map) [menu-bar index]))
       (let ((newmap (make-sparse-keymap)))
 	(set-keymap-parent newmap (current-local-map))
 	(setq imenu--last-menubar-index-alist nil)
 	(define-key newmap [menu-bar index]
 	  `(menu-item ,name ,(make-sparse-keymap "Imenu")))
 	(use-local-map newmap)
-	(add-hook 'menu-bar-update-hook 'imenu-update-menubar))
+	  (add-hook 'menu-bar-update-hook 'imenu-update-menubar)))
     (error "The mode `%s' does not support Imenu"
            (format-mode-line mode-name))))
 
@@ -1008,6 +1009,9 @@
 						   (car (cdr menu))))
 					    'imenu--menubar-select))
 	  (setq old (lookup-key (current-local-map) [menu-bar index]))
+	  ;; This should never happen, but in some odd cases, potentially,
+	  ;; lookup-key may return a dynamically composed keymap.
+	  (if (keymapp (cadr old)) (setq old (cadr old)))
 	  (setcdr old (cdr menu1)))))))
 
 (defun imenu--menubar-select (item)