bug#66326: 29.1.50; There should be a way to promote warnings to errors

[Spencer Baugh]

It's common in other languages to have a flag such as -Werror to turn
warnings into errors.  This is useful if you're writing some code and
you want to be scrupulous about preventing potential bugs; if code would
warn, you just want to error instead of trying to continue running.

It would be nice to have this feature in Emacs Lisp.

I've personally frequently had trouble with figuring out where exactly a
warning is triggered from.  I eventually settled on (debug-on-warning
'display-warning) and looking at *Backtrace*, but it would be nicer to
just make all warnings into errors which could be handled using whatever
normal error mechanism - which might or might not be the debugger.

I'll implement this feature in a subsequent patch.


In GNU Emacs 29.1.50 (build 4, x86_64-pc-linux-gnu, X toolkit, cairo
 version 1.15.12, Xaw scroll bars) of 2023-09-11 built on

Repository revision: f9bc92d0b36bc631d11c194e4b580f43b7b8dcba
Repository branch: emacs-29
Windowing system distributor 'The X.Org Foundation', version 11.0.12011000
System Description: Rocky Linux 8.8 (Green Obsidian)

Configured using:
 'configure --config-cache --with-x-toolkit=lucid
 --with-gif=ifavailable'

Configured features:
CAIRO DBUS FREETYPE GLIB GMP GNUTLS GSETTINGS HARFBUZZ JPEG JSON
LIBSELINUX LIBSYSTEMD LIBXML2 MODULES NOTIFY INOTIFY PDUMPER PNG RSVG
SECCOMP SOUND SQLITE3 THREADS TIFF TOOLKIT_SCROLL_BARS X11 XDBE XIM
XINPUT2 XPM LUCID ZLIB

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

Major mode: Markdown
Memory information:
((conses 16 4175004 208691)
 (symbols 48 59948 1)
 (strings 32 259924 33150)
 (string-bytes 1 10506599)
 (vectors 16 91335)
 (vector-slots 8 2087528 344365)
 (floats 8 615 413)
 (intervals 56 366721 1629)
 (buffers 976 282))