Hi,

I have updated the attached patch to use `mapconcat' as requested.
`org-format-latex-header' is already declared earlier in ob-latex.el.

I am not sure what kind of test you have in mind, since this feature isn't
completely internal to org-mode. For example, the preview compiles but the
produced PDF is incorrect before this fix, and I believe the org preview
machinery ignores errors from the latex compiler.

Best,

YL

On Thu, May 7, 2020 at 1:37 PM Nicolas Goaziou <mail@nicolasgoaziou.fr>
wrote:

> Hello,
>
> Yuri Lensky <ydl@ydl.cm> writes:
>
> > Subject: [PATCH] lisp/ob-latex.el: Stop ignoring headers argument
>
> Thank you.
>
> > During default "png" export, the "headers" argument is no longer
> > explicitly ignored.
>
> According to the TODO in that function, this is not the first time it
> happens. Would you mind writing a test for it?
>
> > +          (let ((org-format-latex-header
> > +              (concat org-format-latex-header "\n"
> > +                      (string-join headers "\n"))))
> > +        (org-create-formula-image
> > +            body out-file org-format-latex-options in-buffer)))
>
> This looks hackish but I don't know how to do it otherwise. However
> could you use `mapconcat' instead of `string-join'?
>
> Also, you need to declare `org-format-latex-header' in order to silence
> byte-compiler.
>
> Regards,
>
> --
> Nicolas Goaziou
>