bug#71227: 29.2; show-paren-context-when-offscreen does not show previous line for OCaml "begin" opener

bug#71227: 29.2; show-paren-context-when-offscreen does not show previous line for OCaml "begin" opener

[Gaëtan Gilbert]

eg if you make a file containing

   let foo =
     begin

     ()

     end

scroll so that the begin is hidden and highlight end,
show-paren-context-when-offscreen will only show the "begin" line but should also show the "let foo" line.

I guess this is because "begin" is not a single character.

Can be reproduced in emacs -Q after loading tuareg-opam.el, tuareg-compat.el and tuareg.el from https://github.com/ocaml/tuareg
by using tuareg-mode on the above example and setting show-paren-context-when-offscreen to your preferred non-nil value.

------ stuff report-emacs-bug said:

In GNU Emacs 29.2 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.24.41,
  cairo version 1.18.0) of 2024-02-27, modified by Debian built on
  x86-ubc-02
Windowing system distributor 'The X.Org Foundation', version 11.0.12101011
System Description: Debian GNU/Linux trixie/sid

Configured using:
  'configure --build x86_64-linux-gnu --prefix=/usr
  --sharedstatedir=/var/lib --libexecdir=/usr/libexec
  --localstatedir=/var/lib --infodir=/usr/share/info
  --mandir=/usr/share/man --with-libsystemd --with-pop=yes
  --enable-locallisppath=/etc/emacs:/usr/local/share/emacs/29.2/site-lisp:/usr/local/share/emacs/site-lisp:/usr/share/emacs/29.2/site-lisp:/usr/share/emacs/site-lisp
  --with-sound=alsa --without-gconf --with-mailutils
  --with-native-compilation --build x86_64-linux-gnu --prefix=/usr
  --sharedstatedir=/var/lib --libexecdir=/usr/libexec
  --localstatedir=/var/lib --infodir=/usr/share/info
  --mandir=/usr/share/man --with-libsystemd --with-pop=yes
  --enable-locallisppath=/etc/emacs:/usr/local/share/emacs/29.2/site-lisp:/usr/local/share/emacs/site-lisp:/usr/share/emacs/29.2/site-lisp:/usr/share/emacs/site-lisp
  --with-sound=alsa --without-gconf --with-mailutils
  --with-native-compilation --with-cairo --with-x=yes
  --with-x-toolkit=gtk3 --with-toolkit-scroll-bars 'CFLAGS=-g -O2
  -ffile-prefix-map=/build/reproducible-path/emacs-29.2+1=. -fstack-protector-strong
  -fstack-clash-protection -Wformat -Werror=format-security
  -fcf-protection -Wall' 'CPPFLAGS=-Wdate-time -D_FORTIFY_SOURCE=2'
  LDFLAGS=-Wl,-z,relro'

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

Important settings:
   value of $LC_MONETARY: fr_FR.UTF-8
   value of $LC_TIME: fr_FR.UTF-8
   value of $LANG: en_US.UTF-8
   locale-coding-system: utf-8-unix

Major mode: Lisp Interaction

Minor modes in effect:
   tooltip-mode: t
   global-eldoc-mode: t
   eldoc-mode: t
   show-paren-mode: t
   electric-indent-mode: t
   mouse-wheel-mode: t
   tool-bar-mode: t
   menu-bar-mode: t
   file-name-shadow-mode: t
   global-font-lock-mode: t
   font-lock-mode: t
   blink-cursor-mode: t
   line-number-mode: t
   indent-tabs-mode: t
   transient-mark-mode: t
   auto-composition-mode: t
   auto-encryption-mode: t
   auto-compression-mode: t

Load-path shadows:
None found.

Features:
(shadow sort mail-extr emacsbug message mailcap yank-media puny dired
dired-loaddefs rfc822 mml mml-sec password-cache epa epg rfc6068
epg-config gnus-util time-date mm-decode mm-bodies mm-encode mail-parse
rfc2231 mailabbrev gmm-utils mailheader sendmail rfc2047 rfc2045
ietf-drums mm-util mail-prsvr mail-utils tuareg pcase find-file
tuareg-compat tuareg-opam derived skeleton flymake-proc flymake project
byte-opt compile text-property-search comint ansi-osc ansi-color ring
thingatpt cl-loaddefs comp comp-cstr warnings icons subr-x rx cl-seq
cl-macs gv cl-extra help-mode bytecomp byte-compile cl-lib smie rmc
iso-transl tooltip cconv eldoc paren electric uniquify ediff-hook
vc-hooks lisp-float-type elisp-mode mwheel term/x-win x-win
term/common-win x-dnd tool-bar dnd fontset image regexp-opt fringe
tabulated-list replace newcomment text-mode lisp-mode prog-mode register
page tab-bar menu-bar rfn-eshadow isearch easymenu timer select
scroll-bar mouse jit-lock font-lock syntax font-core term/tty-colors
frame minibuffer nadvice seq simple cl-generic indonesian philippine
cham georgian utf-8-lang misc-lang vietnamese tibetan thai tai-viet lao
korean japanese eucjp-ms cp51932 hebrew greek romanian slovak czech
european ethiopic indian cyrillic chinese composite emoji-zwj charscript
charprop case-table epa-hook jka-cmpr-hook help abbrev obarray oclosure
cl-preloaded button loaddefs theme-loaddefs faces cus-face macroexp
files window text-properties overlay sha1 md5 base64 format env
code-pages mule custom widget keymap hashtable-print-readable backquote
threads dbusbind inotify lcms2 dynamic-setting system-font-setting
font-render-setting cairo move-toolbar gtk x-toolkit xinput2 x multi-tty
make-network-process native-compile emacs)

Memory information:
((conses 16 117115 7416)
  (symbols 48 9114 0)
  (strings 32 26230 2538)
  (string-bytes 1 797200)
  (vectors 16 18127)
  (vector-slots 8 371815 15174)
  (floats 8 52 24)
  (intervals 56 360 0)
  (buffers 984 15))

--
Gaëtan Gilbert

bug#71227: 29.2; show-paren-context-when-offscreen does not show previous line for OCaml "begin" opener

[Eli Zaretskii]

> Date: Mon, 27 May 2024 14:50:13 +0200
> From: Gaëtan Gilbert <gaetan.gilbert@skyskimmer.net>
> 
> eg if you make a file containing
> 
>    let foo =
>      begin
> 
>      ()
> 
>      end
> 
> scroll so that the begin is hidden and highlight end,
> show-paren-context-when-offscreen will only show the "begin" line but should also show the "let foo" line.
> 
> I guess this is because "begin" is not a single character.
> 
> Can be reproduced in emacs -Q after loading tuareg-opam.el, tuareg-compat.el and tuareg.el from https://github.com/ocaml/tuareg
> by using tuareg-mode on the above example and setting show-paren-context-when-offscreen to your preferred non-nil value.

Thanks, but shouldn't this problem be reported to the developers of
these packages first?  Those packages are not part of Emacs and not on
ELPA, AFAICT.