[luatex] \luaescapestring and \escapechar

[Joseph Wright]

Hello all,

Running some tests today I stumbled across the following issue. With the
demo:

    \def\test{\luaescapestring{\noexpand\foo}}
    \escapechar=-1\relax
    \test

I get

    This is LuaTeX, Version beta-0.79.1 (TeX Live 2014) (rev 4971)
     restricted \write18 enabled.
    (./test.tex
    ! String contains an invalid utf-8 sequence.
    test ^^@-luaescapestring {noexpand foo }

    l.3 \test

    ?

I was as you'd imagined a bit surprised: I spent a while looking over my
source for dodgy input before concluding there is something more subtle up.

Is this in some way deliberate or a bug?
-- 
Joseph Wright