[O] [Bug] beamer backend and org-reload

[Suvayu Ali]

Hi Achim,

On Tue, Mar 05, 2013 at 07:26:54PM +0100, Achim Gratz wrote:
> Suvayu Ali writes:
> > That said, I have noticed something odd about the new exporter and
> > org-reload.  I think with the new exporter after doing org-reload, org
> > related config is not reloaded properly.
> 
> Config is not reloaded at all (and never has been), any configuration
> variables that are already existing are not touched when the file gets
> reloaded.
> 
> > This borks the Org instance.  This is more visible when using the
> > Beamer backend since it requires customisation of org-latex-classes by
> > the user.  One of these days, I'll try to come up with a proper recipe
> > to reproduce this.
> 
> Please do, this should not happen.

Here is the recipe:

1. emacs -nw -Q -l ~/minimal-org.el

   ;;; minimal-org.el: Minimal setup to load latest `org-mode'
   
   ;;; Code:
   (setq debug-on-error t
         debug-on-signal nil
         debug-on-quit nil)
   
   (add-to-list 'load-path (expand-file-name "~/build/org-mode/lisp"))
   
   (require 'ox-beamer)
   (add-to-list 'org-latex-classes
                '("beamer"
                  "\\documentclass\[presentation\]\{beamer\}"
                  ("\\section\{%s\}" . "\\section*\{%s\}")
                  ("\\subsection\{%s\}" . "\\subsection*\{%s\}")
                  ("\\subsubsection\{%s\}" . "\\subsubsection*\{%s\}")))

2. C-x C-f some-file.org RET
3. Now try to export: C-c C-e.  You can see menu options for beamer export.
4. Now reload Org: C-c C-x !.  Try step 3 again.  You will notice the
   entries for beamer is missing.

This might actually be a problem with ox-beamer and not org-reload
because I noticed my other Org customisations do stay intact (which is
of course in line with your comment about settings not being touched).

Instead of step (3), you could also try M-x org-beamer-export-as-latex.
After step (4), repeating this alternate step (3) should give you the
following backtrace.

Debugger entered--Lisp error: (error "Unknown \"beamer\" back-end: Aborting 
export")
  signal(error ("Unknown \"beamer\" back-end: Aborting export"))
  error("Unknown \"%s\" back-end: Aborting export" beamer)
  org-export-barf-if-invalid-backend(beamer)
  org-export-as(beamer nil nil nil nil)
  org-export-to-buffer(beamer "*Org BEAMER Export*" nil nil nil nil)
  org-beamer-export-as-latex()
  call-interactively(org-beamer-export-as-latex record nil)
  command-execute(org-beamer-export-as-latex record)
  execute-extended-command(nil "org-beamer-export-as-latex")
  call-interactively(execute-extended-command nil nil)
  command-execute(execute-extended-command)

Hopefully my recipe is complete to fix this issue.

Cheers,

-- 
Suvayu

Open source is the future. It sets us free.