Re: Possibly Bug in function org-scan-tags

[Nick Dokos <nicholas.dokos@hp.com>]

bala mayam <balamayam@gmail.com> wrote:

> The patch has error, it does not work for the following example file
> /tmp/example.org
> * DONE s1
> * DONE s2
> * DONE s3
> 
> The below patch works for all the cases
> 
> diff --git a/lisp/org.el b/lisp/org.el
> index 8a1fbd3..93d603f 100644
> --- a/lisp/org.el
> +++ b/lisp/org.el
> @@ -12858,7 +12858,8 @@ only lines with a TODO keyword are included in the outpu
>         ;; Get the correct position from where to continue
>         (if org-map-continue-from
>             (goto-char org-map-continue-from)
> -         (and (= (point) lspos) (end-of-line 1)))))
> +         (and (= (point) lspos) (end-of-line 1)))
> +       (setq org-map-continue-from nil)))
>      (when (and (eq action 'sparse-tree)
>                (not org-sparse-tree-open-archived-trees))
>        (org-hide-archived-subtrees (point-min) (point-max)))
> 
> - Balamayam
> 
> On Thu, Dec 15, 2011 at 3:18 AM, bala subramaniyam <balamayam@gmail.com> wrote:
> 
>     Hi,
>                  The variable "org-map-continue-from" is not reset to nil after the funcall to action
>     in function "org-scan-tags".
>    
>     Heres the patch which works
>    
>     diff --git a/lisp/org.el b/lisp/org.el
>     index 8a1fbd3..54ab5fb 100644
>     --- a/lisp/org.el
>     +++ b/lisp/org.el
>     @@ -12848,7 +12848,8 @@ only lines with a TODO keyword are included in the output."
>                   (setq org-map-continue-from nil)
>                   (save-excursion
>                     (setq rtn1 (funcall action))
>     -               (push rtn1 rtn)))
>     +               (push rtn1 rtn))
>     +             (setq org-map-continue-from nil))
>                  (t (error "Invalid action")))
>      
>                 ;; if we are to skip sublevels, jump to end of subtree
>    
>     To see the error in action assume that we want to archive all the "DONE" states in the file
>     /tmp/test.org which contains the following lines.
>     * s1
>     ** DONE ss1
>     ** NEXT ss2
> 
>     (defun my-org-archive-subtree ()
>       (setq org-map-continue-from (point-at-bol))
>       (org-archive-subtree))
>    
>      (org-map-entries 'my-org-archive-subtree "/DONE" (list "/tmp/test.org"))
>    
>     While the org-scan-tags funciton parses the first subheading(**DONE ss1) the match is
>     successful and the function "my-org-archive-subtree" is called which sets the variable
>     "org-map-continue-from" value to *beginning of line* and this variable is not set back to nil
>     after the function call ends, which leads to infinite loop while parsing the subsequent headlines
>     which does not match the "DONE" state(**NEXT ss2).
>    

I think it's a bit much to expect org to avoid all possible infinite loops
that a user function can get it into - it's up to you to write the function
properly so that it does *not* lead to infinite loops.

In this case, I think you can write

--8<---------------cut here---------------start------------->8---
(defun my-org-archive-subtree ()
  (let ((org-map-continue-from (point-at-bol)))
    (org-archive-subtree)))
--8<---------------cut here---------------end--------------->8---

and be done with it - no changes to org needed. AFAICT, it deals with
both of your examples without going into an infinite loop.

What am I missing?

Nick