* bug#13438: /srv/bzr/emacs/emacs-24 r111196: * imenu.el (imenu-default-create-index-function): Remove useless
[not found] <E1Ty8dP-0000cA-TK@vcs.savannah.gnu.org>
@ 2013-01-24 18:01 ` Glenn Morris
2013-01-24 18:30 ` Stefan Monnier
0 siblings, 1 reply; 5+ messages in thread
From: Glenn Morris @ 2013-01-24 18:01 UTC (permalink / raw)
To: Fabián Ezequiel Gallina; +Cc: 13438
> * imenu.el (imenu-default-create-index-function): Remove useless
> infinite loop check.
[...]
> --- a/lisp/imenu.el 2013-01-01 09:11:05 +0000
> +++ b/lisp/imenu.el 2013-01-23 21:55:46 +0000
> @@ -683,8 +683,6 @@
> (goto-char (point-max))
> ;; Search for the function
> (while (funcall imenu-prev-index-position-function)
> - (when (= pos (point))
> - (error "Infinite loop at %s:%d: imenu-prev-index-position-function does not move point" (buffer-name) pos))
> (setq pos (point))
> (save-excursion
> (setq name (funcall imenu-extract-index-name-function)))
I'm not keen on removing an infinite loop check from emacs-24 at this
stage. Why is this issue (apparently) only seen in Python mode, and why
isn't there a Python-specific solution (which seems like it would be
just making imenu-prev-index-position-function return nil when
appropriate)?
Related discussion:
http://lists.gnu.org/archive/html/emacs-devel/2013-01/msg00536.html
^ permalink raw reply [flat|nested] 5+ messages in thread
* bug#13438: /srv/bzr/emacs/emacs-24 r111196: * imenu.el (imenu-default-create-index-function): Remove useless
2013-01-24 18:01 ` bug#13438: /srv/bzr/emacs/emacs-24 r111196: * imenu.el (imenu-default-create-index-function): Remove useless Glenn Morris
@ 2013-01-24 18:30 ` Stefan Monnier
2013-01-25 8:34 ` Glenn Morris
0 siblings, 1 reply; 5+ messages in thread
From: Stefan Monnier @ 2013-01-24 18:30 UTC (permalink / raw)
To: Glenn Morris; +Cc: Fabián Ezequiel Gallina, 13438
> I'm not keen on removing an infinite loop check from emacs-24 at this
> stage.
The patch is "safe" in the sense that it will only introduce
an inf-loop in those cases where the user used to get an error.
[ Unless of course, the calling context catches those errors. ]
> Why is this issue (apparently) only seen in Python mode, and why
> isn't there a Python-specific solution (which seems like it would be
> just making imenu-prev-index-position-function return nil when
> appropriate)?
If we can change python.el to work around the problem, we could install
that workaround in emacs-24 and keep the "remove the inf-loop check" for
the trunk, indeed.
Stefan
^ permalink raw reply [flat|nested] 5+ messages in thread
* bug#13438: /srv/bzr/emacs/emacs-24 r111196: * imenu.el (imenu-default-create-index-function): Remove useless
2013-01-24 18:30 ` Stefan Monnier
@ 2013-01-25 8:34 ` Glenn Morris
2013-01-25 13:55 ` Fabián Ezequiel Gallina
0 siblings, 1 reply; 5+ messages in thread
From: Glenn Morris @ 2013-01-25 8:34 UTC (permalink / raw)
To: Stefan Monnier; +Cc: Fabián Ezequiel Gallina, 13438
>> Why is this issue (apparently) only seen in Python mode
Answering my own question, it happens in any mode that sets
imenu-prev-index-position-function and
imenu-extract-index-name-function, but there are very few of those.
Eg prolog mode. With buffer contents:
------
fac(0,1).
fac(N,F) :- N > 0, M is N - 1,
fac(M,Fm), F is N * Fm.
------
and point at point-min, switching to prolog-mode causes the same issue.
How about taking the more cautious approach with:
(when (and (= pos (point))
(not (bobp)))
(error "Infinite loop... ))
(IIUC, this was actually the suggestion in
http://lists.gnu.org/archive/html/emacs-devel/2013-01/msg00510.html ?)
^ permalink raw reply [flat|nested] 5+ messages in thread
* bug#13438: /srv/bzr/emacs/emacs-24 r111196: * imenu.el (imenu-default-create-index-function): Remove useless
2013-01-25 8:34 ` Glenn Morris
@ 2013-01-25 13:55 ` Fabián Ezequiel Gallina
2013-01-27 2:12 ` Glenn Morris
0 siblings, 1 reply; 5+ messages in thread
From: Fabián Ezequiel Gallina @ 2013-01-25 13:55 UTC (permalink / raw)
To: Glenn Morris; +Cc: 13438
[-- Attachment #1: Type: text/plain, Size: 1927 bytes --]
On 01/25/2013 05:34 AM, Glenn Morris wrote:
>>> Why is this issue (apparently) only seen in Python mode
> Answering my own question, it happens in any mode that sets
> imenu-prev-index-position-function and
> imenu-extract-index-name-function, but there are very few of those.
>
> Eg prolog mode. With buffer contents:
>
> ------
> fac(0,1).
> fac(N,F) :- N > 0, M is N - 1,
> fac(M,Fm), F is N * Fm.
> ------
>
> and point at point-min, switching to prolog-mode causes the same issue.
>
> How about taking the more cautious approach with:
>
> (when (and (= pos (point))
> (not (bobp)))
> (error "Infinite loop... ))
>
> (IIUC, this was actually the suggestion in
> http://lists.gnu.org/archive/html/emacs-devel/2013-01/msg00510.html ?)
I ran into the same thing, and checking bobp is not enough, try adding a
newline at the beginning of file to the recipe and call imenu with point
at beginning of defun and you'll see the infinite error check will trigger.
I proposed the following patch that works:
=== modified file 'lisp/imenu.el'
--- lisp/imenu.el 2013-01-01 09:11:05 +0000
+++ lisp/imenu.el 2013-01-22 18:24:45 +0000
@@ -683,7 +683,14 @@
(goto-char (point-max))
;; Search for the function
(while (funcall imenu-prev-index-position-function)
- (when (= pos (point))
+ (when (and (= pos (point))
+ (= pos
+ (save-excursion
+ ;; The infinite loop is true if there's
+ ;; another index position but point keeps
+ ;; itself in the same place. bug#13438
+ (if (funcall imenu-prev-index-position-
function)
+ (point) 0))))
But finally after some mails with Stefan we decided the best thing will
be to remove this check altogether.
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^ permalink raw reply [flat|nested] 5+ messages in thread
* bug#13438: /srv/bzr/emacs/emacs-24 r111196: * imenu.el (imenu-default-create-index-function): Remove useless
2013-01-25 13:55 ` Fabián Ezequiel Gallina
@ 2013-01-27 2:12 ` Glenn Morris
0 siblings, 0 replies; 5+ messages in thread
From: Glenn Morris @ 2013-01-27 2:12 UTC (permalink / raw)
To: Fabián Ezequiel Gallina; +Cc: 13438
Oh, so the actual issue is: if you call
imenu-default-create-index-function with point at the start of the last
defun in the buffer. It goes to point-max, then back to the start of the
defun, and mistakenly thinks it is inflooping.
How about the following, which only signals an error if
imenu-prev-index-position-function returns non-nil twice in a row
without moving point.
BTW, neither python-nav-beginning-of-defun or
python-imenu-prev-index-position will move past the start of the first
defun in a buffer, if the defun begins past point-min (ie, if there are
blank lines before the first defun, it does not move over them to
point-min). I don't know if this matters, but it is inconsistent with eg
Prolog and Emacs Lisp modes.
*** lisp/imenu.el 2013-01-23 21:55:46 +0000
--- lisp/imenu.el 2013-01-27 02:02:39 +0000
***************
*** 678,688 ****
;; in these major modes. But save that change for later.
(cond ((and imenu-prev-index-position-function
imenu-extract-index-name-function)
! (let ((index-alist '()) (pos (point))
name)
(goto-char (point-max))
;; Search for the function
(while (funcall imenu-prev-index-position-function)
(setq pos (point))
(save-excursion
(setq name (funcall imenu-extract-index-name-function)))
--- 678,690 ----
;; in these major modes. But save that change for later.
(cond ((and imenu-prev-index-position-function
imenu-extract-index-name-function)
! (let ((index-alist '()) (pos -1)
name)
(goto-char (point-max))
;; Search for the function
(while (funcall imenu-prev-index-position-function)
+ (when (= pos (point))
+ (error "Infinite loop at %s:%d: imenu-prev-index-position-function does not move point" (buffer-name) pos))
(setq pos (point))
(save-excursion
(setq name (funcall imenu-extract-index-name-function)))
^ permalink raw reply [flat|nested] 5+ messages in thread
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[not found] <E1Ty8dP-0000cA-TK@vcs.savannah.gnu.org>
2013-01-24 18:01 ` bug#13438: /srv/bzr/emacs/emacs-24 r111196: * imenu.el (imenu-default-create-index-function): Remove useless Glenn Morris
2013-01-24 18:30 ` Stefan Monnier
2013-01-25 8:34 ` Glenn Morris
2013-01-25 13:55 ` Fabián Ezequiel Gallina
2013-01-27 2:12 ` Glenn Morris
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