[luatex] How to get a \mid binary relation that grows in LuaTeX

[Malte Dehling]

Hi everyone,

I posted a question on tex.SE with the subject as title.  In short,
there is a difference in how pdflatex and lualatex handle the expression
$\left(a\mathrel{}\middle|\mathrel{}b\right)$.  Using pdflatex one gets
symmetric spacing around the vertical bar while lualatex produces more
space on the right.  See here for the question and an explanation in the
answer:

https://tex.stackexchange.com/questions/401234/how-to-get-a-mid-binary-relation-that-grows-in-luatex

Is this a bug or intentional behavior?

Best wishes,

-- 
Malte Dehling
<malte.dehling at uni-goettingen.de>