[luatex] Logging of font names in box log output

[David Carlisle]

Hi I have a feeling this has come up before, but  the plain tex file


\font\a=cmr10
\font\b=cmr10

\setbox0\hbox{\a x\b y}
\scrollmode
\tracingonline1
\showbox0
\bye


produces a log of

.\b x
.\b y



in tex/pdftex/xetex/ptex/uptex

but in luatex it produces a log of

.\a x
.\b y

This is a major problem for the latex regression suite as it is very
hard to normalize out (as we do for the direction logging difference
where
"direction TLT" in luatex or  "yoko direction" in  ptex occur in
well defined places and can be factored into the comparison).

Would it be possible for luatex to match other tex variants and log
font names by the last name under which the font was loaded?

David