bug#71258: 29.2.50; insert-file-contents has a confusing error when called on a directory

[Spencer Baugh <sbaugh@janestreet.com>]

1. emacs -Q
2. M-: (insert-file-contents "~") RET
3. Observe (error "Maximum buffer size exceeded") since ~ is a directory.

This is quite confusing as an error message, it should be something else
instead.


In GNU Emacs 29.2.50 (build 2, x86_64-pc-linux-gnu, X toolkit, cairo
 version 1.15.12, Xaw scroll bars) of 2024-05-21 built on
 igm-qws-u22796a
Windowing system distributor 'The X.Org Foundation', version 11.0.12011000
System Description: Rocky Linux 8.9 (Green Obsidian)

Configured using:
 'configure --config-cache --with-x-toolkit=lucid --without-gpm
 --without-gconf --without-selinux --without-imagemagick --with-modules
 --with-gif=no --with-cairo --with-rsvg --without-compress-install
 --prefix=/j/office/app/emacs/builds/29-20240521-160155'

Configured features:
CAIRO DBUS FREETYPE GLIB GMP GNUTLS GSETTINGS HARFBUZZ JPEG JSON
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 $EMACSLOADPATH: /usr/local/home/sbaugh/workspaces/a214bae1-d596-34a8-e114-b7c0749d60cb/+share+/app/emacs/lib/ecaml_plugin/bin:/usr/local/home/sbaugh/workspaces/a214bae1-d596-34a8-e114-b7c0749d60cb/+share+/app/emacs/elisp:
  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:
/usr/local/home/sbaugh/workspaces/a214bae1-d596-34a8-e114-b7c0749d60cb/+share+/app/emacs/elisp/spacemacs-layers/jane/config hides /usr/local/home/sbaugh/workspaces/a214bae1-d596-34a8-e114-b7c0749d60cb/+share+/app/emacs/elisp/spacemacs-layers/jane-dap/config
/usr/local/home/sbaugh/workspaces/a214bae1-d596-34a8-e114-b7c0749d60cb/+share+/app/emacs/elisp/spacemacs-layers/jane/packages hides /usr/local/home/sbaugh/workspaces/a214bae1-d596-34a8-e114-b7c0749d60cb/+share+/app/emacs/elisp/spacemacs-layers/jane-dap/packages
/usr/local/home/sbaugh/workspaces/a214bae1-d596-34a8-e114-b7c0749d60cb/+share+/app/emacs/elisp/spacemacs-layers/jane/packages hides /usr/local/home/sbaugh/workspaces/a214bae1-d596-34a8-e114-b7c0749d60cb/+share+/app/emacs/elisp/spacemacs-layers/jane-fzf/packages
/usr/local/home/sbaugh/workspaces/a214bae1-d596-34a8-e114-b7c0749d60cb/+share+/app/emacs/elisp/spacemacs-layers/jane/config hides /usr/local/home/sbaugh/workspaces/a214bae1-d596-34a8-e114-b7c0749d60cb/+share+/app/emacs/elisp/spacemacs-layers/jane-fzf/config
/usr/local/home/sbaugh/workspaces/a214bae1-d596-34a8-e114-b7c0749d60cb/+share+/app/emacs/elisp/spacemacs-layers/jane/packages hides /usr/local/home/sbaugh/workspaces/a214bae1-d596-34a8-e114-b7c0749d60cb/+share+/app/emacs/elisp/spacemacs-layers/org-fe/packages
/usr/local/home/sbaugh/workspaces/a214bae1-d596-34a8-e114-b7c0749d60cb/+share+/app/emacs/elisp/contrib/eglot/jsonrpc hides /j/office/app/emacs/builds/29-20240521-160155/share/emacs/29.2.50/lisp/jsonrpc
/usr/local/home/sbaugh/workspaces/a214bae1-d596-34a8-e114-b7c0749d60cb/+share+/app/emacs/elisp/contrib/eglot/external-completion hides /j/office/app/emacs/builds/29-20240521-160155/share/emacs/29.2.50/lisp/external-completion
/usr/local/home/sbaugh/workspaces/a214bae1-d596-34a8-e114-b7c0749d60cb/+share+/app/emacs/elisp/contrib/eglot/eglot hides /j/office/app/emacs/builds/29-20240521-160155/share/emacs/29.2.50/lisp/progmodes/eglot
/usr/local/home/sbaugh/workspaces/a214bae1-d596-34a8-e114-b7c0749d60cb/+share+/app/emacs/elisp/contrib/auctex/lpath hides /usr/local/home/sbaugh/workspaces/a214bae1-d596-34a8-e114-b7c0749d60cb/+share+/app/emacs/elisp/contrib/dictionary/lpath
/j/office/app/emacs/builds/29-20240521-160155/share/emacs/29.2.50/lisp/net/dictionary hides /usr/local/home/sbaugh/workspaces/a214bae1-d596-34a8-e114-b7c0749d60cb/+share+/app/emacs/elisp/contrib/dictionary/dictionary

Features:
(shadow sort mail-extr emacsbug message mailcap yank-media puny dired
dired-loaddefs rfc822 mml mml-sec password-cache epa derived epg rfc6068
epg-config gnus-util text-property-search time-date subr-x mm-decode
mm-bodies mm-encode mail-parse rfc2231 mailabbrev gmm-utils mailheader
sendmail rfc2047 rfc2045 ietf-drums mm-util mail-prsvr mail-utils
help-fns radix-tree cl-print byte-opt gv bytecomp byte-compile debug
backtrace help-mode find-func cl-loaddefs cl-lib 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
dynamic-setting system-font-setting font-render-setting cairo x-toolkit
xinput2 x multi-tty make-network-process emacs)

Memory information:
((conses 16 74527 9721)
 (symbols 48 10533 0)
 (strings 32 26606 1294)
 (string-bytes 1 817294)
 (vectors 16 11698)
 (vector-slots 8 171912 11362)
 (floats 8 36 38)
 (intervals 56 308 0)
 (buffers 976 11))