Re: [PATCH] Add catch-up all LaTeX errors

[Sebastien Vauban <sva-news-D0wtAvR13HarG/iDocfnWg@public.gmane.org>]

Nicolas Goaziou wrote:
> "Francesco Pizzolante" <fpz-djc/iPCCuDYQheJpep6IedvLeJWuRmrY@public.gmane.org> writes:
>
>>> IOW, it cannot tell the difference between a successful export and an
>>> export failure with an already existing PDFFILE.
>>
>> This is not true as this code checks for the `errors' variable in all
>> cases. With an already existing PDFFILE, you will end up with this
>> message: 'Process completed with errors: ...'.
>
> If "file.pdf" exists before the export, you will always get "Process
> completed", even if the current export was a total failure (e.g., no
> file produced).
>
> IIUC, you're really looking after a way to know if a pdf file was really
> produced. Reporting "Process completed with errors : [unknown error]"
> will certainly not help on this you because some errors are not fatal
> (i.e., they are skipped and the pdf file is still produced).
>
>> From my point of view, the issue comes from the fact that the `errors'
>> variable is not correctly filled in with errors from the LaTeX log file.
>
> [...]
>
>> While the wikibooks reference
>> (http://en.wikibooks.org/wiki/LaTeX/Errors_and_Warnings) tells that to
>> be sure to catch *all* errors, we have to check for any line beginning
>> with '!'.
>
> I agree, but this is not sufficient, see below.
>
>> Then, in the case where the `errors' variable would effectively contain
>> any error from the log file, the code you mention above would work in
>> any case.
>>
>> That's why I started with this patch (*and it works*):
>
> It depends on what you define as "working". We're talking about two
> different things. I think a better error system should report:
>
>   1. a PDF file not produced (or updated),
>   2. a PDF file produced with errors,
>   3. a PDF file produced with warnings (maybe),
>   4. a PDF file produced cleanly.
>
> 4 already works. Your patch improves 2, but 1 is still wrong.

FWIW, I'm using this in some export code I have:

--8<---------------cut here---------------start------------->8---
      (let* ((orgfile (buffer-file-name))
             (base-name (file-name-base orgfile))
             (htmlfile (concat base-name ".html"))
             (pdffile (concat base-name ".pdf")))
          ...
          (when (file-exists-p pdffile)
            (if (file-newer-than-file-p orgfile pdffile)
                  (org-latex-export-to-pdf)
              (message "PDF is up to date with Org file"))))
--8<---------------cut here---------------end--------------->8---

That way, we know if the PDF file has been (re-)produced: it must be
newer than the Org file...

Best regards,
  Seb

-- 
Sebastien Vauban