On Tue, Feb 18, 2020 at 11:44:37PM +0100, luigi scarso wrote:
> On Tue, Feb 18, 2020 at 12:54 PM Marcel Fabian Krüger <tex@2krueger.de>
> wrote:
>
> >
> > A plain LuaTeX example for this would be
> >
> > \directlua{
> >   callback.register('kerning', node.kerning)
> >
> >   font.current(font.define {
> >     name = "dummy",
> >     type = "virtual",
> >     characters = {
> >       {
> >         width = 655360,
> >         height = 655360,
> >         depth = 655360,
> >         commands = {},
> >       },
> >       right_boundary = {
> >         width = 655360,
> >         height = 655360,
> >         depth = 655360,
> >       },
> >     },
> >   })
> > }
> > \char1
> > \bye
> >
> >
> this fails with
>
> (see the transcript file for additional
> information)</opt/luatex/mkvi-experimen
> tal-53/tex/texmf/fonts/opentype/public/lm/lmroman10-regular.otf>
> ! error:  (file dummy) (type 3): font dummy at 72 not found
>
> --
> luigi

Right, I forgot that LuaTeX is not particularly happy about empty
commandds tables. But after replacing

  commands = {}

by

  commands = {{"right", 0}}

and adding some f.fonts table the not found error disappears. But I am
surprised that it even got that far for you: On my system (vanilla
TeXLive 2019 on (Arch) Linux, both with the regular LuaTeX 1.10 and the
current head of "experimental") the actual issue "invalid list tail,
probably missing glue" appears long before LuaTeX reaches the font embedding stage.