On Mon, Jun 21, 2021 at 5:03 PM Marcel Krüger
Hi,
consider the following plain LuaTeX document:
\textdir TRT \noindent\par \bye
without the `\textdir TRT` line or with `\textdir TLT`, this would lead to "warning (pdf backend): no pages of output.", but with the non default "\textdir", it creates an empty (except for the page number) page instead.
This can be avoided by setting \pardir too:
\textdir TRT\pardir TRT \noindent\par \bye
again produces no output, but adding a group around it reintroduces the issue:
\begingroup \textdir TRT\pardir TRT \noindent\par \endgroup \bye
leads to an empty page.
Of course similar things happen not only for otherwise empty documents: Instead of empty paragraphs disappearing, they add empty lines.
Together, this is not only inconsistent with other engines which always discard empty paragraphs, but also leads to hard to predict behavior (especially for users who are not familiar with the implementation of LuaTeX's directional system), so I think it would be great if LuaTeX could always remove such empty paragraphs.
Best, Marcel
confirmed. -- luigi