[Bug-AUCTeX] Re: 11.85; PDF file deleted when generating previews

[Ralf Angeli]

* David Reitter (2009-02-09) writes:

> - In AUCTeX (latest release) with PDF mode on, using the command bound  
> to the menu item "(or toggle) at point", the .pdf file associated with  
> the master file for the current .tex source is deleted.  This is  
> annoying; among the problems it causes is the reported one quoted below.
>
> It appears that the .pdf file is deleted towards the end of the  
> preview generation; this is noticeable when running the slower  
> "generate previews for buffer".
>
> Further investigation shows that the .pdf file is deleted by preview- 
> gs-sentinel because it is the car of `preview-ps-file'.

AFAICS there might be two problems:

1) The car of `preview-ps-file' should likely point to _region_.pdf
   because that's the intermediate store for previews before they are
   being extracted to become PNG files.

2) The file given in the car of `preview-ps-file' should likely not be
   deleted in `preview-gs-sentinel'.  The deletion is carried out in
   case there is no associated overlay or the process was killed by a
   signal.  In principle there is an overlay but the information about
   it was deleted in `preview-gs-transact' via `preview-gs-filter'.  So
   it could be intentional that the information about the overlay does
   not survive untill `preview-gs-sentinel'.  If this is the case,
   setting the file to be deleted to _region_.pdf should still help, but
   why bother deleting the file if _region_.tex and the cruft from the
   LaTeX run on it is still lying around?

I'm not sure about either point, so I hope somebody can shed some more
light on this.  In order to make this a bit easier here is a transcript
of the tool chain I've written up during my investigations:

1) Preview-LaTeX on _region_.tex
   Produces: _region_.pdf

   preview-TeX-inline-sentinel --> (preview-call-hook 'open) -->
   preview-gs-open --> preview-dvipng-process-setup -->
   preview-pdf2dsc-process-setup --> preview-start-pdf2dsc (sets car of
   `preview-ps-file' to master file)

2) Preview-PDF2DSC on _region_.pdf
   Produces: _region_.prv/.../preview.dsc

   preview-pdf2dsc-sentinel --> preview-gs-restart (produces PNG files;
   uses `preview-gs-filter' as process filter which pops stuff from
   `preview-gs-outstanding' via `preview-gs-transact')

3) Preview-Ghostscript
   Produces: pr1-1.png

   preview-gs-sentinel (tries to get overlay with
   `preview-gs-behead-outstanding' by popping the car from
   `preview-gs-outstanding' but there is none; deletes file given in car
   of `preview-ps-file' if overlay is nil or the process was killed by a
   signal)

-- 
Ralf