Hello,
with the following I get an orphan enddir node
==============================
run \linedirection=1 run \linedirection=0 run
run \linedirection=1 run
\bye
=============================
This can confuse the par builder in some situations, and even worse it can confuse the code in pdflistout.c
Another example, where the confusion is visible, is
=================================
run \linedirection=1 run \linedirection=0 run
run {\linedirection=1 run} run \linedirection=1 run
\bye=================================
Note how the last "run" (or nur with direction) is at the bottom left corner.
In fact, anything in the problematic line that is after the problematic point is being shifted,
and after the line break things are restored:
============================
run \linedirection=1 run \linedirection=0 run
run {\linedirection=1 run} run \linedirection=1 run \linedirection=0 run Some more\hfill\break text
\bye
============================
I think this is because when hlist_out() encounters the orphan enddir node the
coordinate system gets corrupted because the orphan enddir causing it the be restored
to bogus saved values.
The enddir node is inserted in https://gitlab.lisn.upsaclay.fr/texlive/luatex/-/blob/master/source/texk/we…
or (with \textdirection) in https://gitlab.lisn.upsaclay.fr/texlive/luatex/-/blob/master/source/texk/we…
Udi
