[LyX/master] Rerun latex if necessary when generating previews

[Enrico Forestieri]

On Mon, May 19, 2025 at 09:34:54PM +0000, Enrico Forestieri wrote:
> 
>commit 1888d50eb18277fd93aab2859233887ae5919ebf
>Author: Enrico Forestieri <forenr at lyx.org>
>Date:   Mon May 19 23:19:15 2025 +0200
>
>    Rerun latex if necessary when generating previews
>
>    Recent versions of dvipng may produce a last page whose content
>    simply states that "LaTeX was unable to guess the total number
>    of pages correctly. As there was some unprocessed data that
>    should have been added to the final page this extra page has
>    been added to receive it. If you rerun the document (without
>    altering it) this surplus page will go away, because LaTeX now
>    knows how many pages to expect for this document."
>
>    This confuses the lyxpreview2bitmap.py script, making it unable
>    to distinguish pages that should follow the dvipng route or the
>    legacy route. However, the presence of the extra page is reported
>    in the log file and hence we know we have to rerun latex.


Riki, this is also needed in stable.

>---
> lib/scripts/lyxpreview_tools.py | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
>diff --git a/lib/scripts/lyxpreview_tools.py b/lib/scripts/lyxpreview_tools.py
>index 56ff33e38b..27ddf22695 100644
>--- a/lib/scripts/lyxpreview_tools.py
>+++ b/lib/scripts/lyxpreview_tools.py
>@@ -293,7 +293,8 @@ def run_latex(latex, latex_file, bibtex = None):
>         latex_status, latex_stdout = run_tex(latex, latex_file)
>     # Rerun latex if necessary
>     progress("Checking if a latex rerun is necessary")
>-    if string_in_file("Warning: (Citation|Reference)", log_file):
>+    if string_in_file("Warning: (Citation|Reference)", log_file) or \
>+       string_in_file("Warning: Temporary extra page", log_file):
>         latex_status, latex_stdout = run_tex(latex, latex_file)
>
>     return latex_status, latex_stdout

-- 
Enrico