[ESS] Strange problem with .Rnw files (emacs-modified-27.2-modified-3)

[Vincent Goulet]

Hi all,

I'm stumbling on a puzzling issue working with .Rnw files using my own Emacs distribution based on ESS 18.10.2. (Annoying since I stay on 27.2 precisely to work with Sweave files the classical ESS way.)

Version 27.2-modified-1 (March 2021) includes AUCTeX 12.3 and works just fine.

The latest (July 2023) version 27.2-modified-3 includes AUCTeX 13.2 and upon visiting a .Rnw file, the LaTeX mode is not activated. The mode line indicates: Fundamental Noweb NWFL. At first I thought this must be an AUCTeX issue or change, but then the only error message I get in the *Messages* buffer is:

File mode specification error: (wrong-type-argument listp ess-inside-string-p)

Any idea what may cause this? To the best of my knowledge, ESS and the initialization files are identical in both versions.

Thanks in advance!

v.

Vincent Goulet
Professeur titulaire
École d'actuariat, Université Laval