In case anyone here has a chance to look ...
Date: Tue, 23 Jan 2018 15:52:19 +0100
From: Enrico Gregorio
To: TeXLive
Subject: [tex-live] Bug in pdftex. Suggestions on who to report?
The following example, compiled with pdftex,
\edef\tenitnumber{\pdffontobjnum\tenit}
\message{The font number is \tenitnumber}
\tenitnumber
\bye
fails with
This is pdfTeX, Version 3.14159265-2.6-1.40.18 (TeX Live 2017) (preloaded format=pdftex)
restricted \write18 enabled.
entering extended mode
(./alfon.tex{/usr/local/texlive/2017/texmf-var/fonts/map/pdftex/updmap/pdftex.m
ap} The font number is 1 [1]Assertion failed: (fo->last_char >= fo->first_char), function create_fontdictionary, file ../../../texk/web2c/pdftexdir/writefont.c, line 607.
)Abort trap: 6
The similar
\edef\first{\pdffeedback fontobjnum\tenit}
\first
\bye
doesnât fail on LuaTeX.
Tested both on Mac OS X and Windows (Joseph Wright tested it). [...]