bug#56135: 29.0.50; python.el - forward-sexp regression over triple-quoted strings

[Kévin Le Gouguec]

Hi!

I believe this commit:

2021-09-21 "Make syntax-ppss more accurate for Python triple quotes
(bug#49518)" (0646c68171)

… introduced a regression for users who set python-forward-sexp-function
to nil (or users who set forward-sexp-function buffer-locally, as was
suggested by python.el's commentary before Emacs 28.1).

To reproduce:

$ echo '"""Quotes for days"""' > repro.py
$ emacs -Q -eval '(setq python-forward-sexp-function nil)' repro.py
; C-M-f

- Point should move to position 22,
- As of the above commit, it lies at position 3.

(Note: if one visits the file before setting the user option, the
setting will not be taken into account; to reproduce, one should then
either set forward-sexp-function directly, or revert the buffer)

I've attached an ert test for this recipe; it passes when run against
0646c68171^ (i.e. the parent commit) and fails as of 0646c68171.

I haven't started to dig into what the change meant to fix, so I cannot
say whether TRT would be to keep the change and improve on it or revert
the change and fix the original problem some other way.

Let me know if I can assist further; thanks for your time.

ert-python-forward-sexp.patch
Description: Text Data

In GNU Emacs 29.0.50 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.24.33, cairo 
version 1.16.0)
 of 2022-05-08 built on amdahl30
Repository revision: e8ed4317e879683872d956cc919d0957fff18531
Repository branch: master
Windowing system distributor 'The X.Org Foundation', version 11.0.12101003
System Description: openSUSE Tumbleweed

Configured using:
 'configure --with-cairo --with-gconf --with-sqlite3 --with-xinput2'

Configured features:
ACL CAIRO DBUS FREETYPE GIF GLIB GMP GNUTLS GPM GSETTINGS HARFBUZZ JPEG
JSON LCMS2 LIBOTF LIBSELINUX LIBSYSTEMD LIBXML2 M17N_FLT MODULES NOTIFY
INOTIFY PDUMPER PNG RSVG SECCOMP SOUND SQLITE3 THREADS TIFF
TOOLKIT_SCROLL_BARS WEBP X11 XDBE XIM XINPUT2 XPM GTK3 ZLIB

Important settings:
  value of $LANG: en_US.UTF-8
  value of $XMODIFIERS: @im=local
  locale-coding-system: utf-8-unix