Subject: 29.2; user-init-file set to .../lisp/progmodes/compile.el.gz

From: Phil Sainty <[email-masked]>
Date: Fri, 01 Mar 2024 01:23:50 +1300

I recently encountered this undesirable side-effect when using the
https://github.com/emacscollective/auto-compile library in conjunction
with a byte-compiled init file.  The combination is reliably resulting
in `user-init-file' being set to the .../lisp/progmodes/compile.el.gz
path, with ensuing chaos (e.g. customized settings being written to
that file -- I first became aware of this problem while using emacs -Q
when it suddenly acquired some custom faces from my regular config as
something loaded the compile library!).

The purpose of the auto-compile package is to ensure that .elc files
are always up-to-date and loaded in preference to .el files.  I've been
using it for many years and wasn't aware of having had any issues with
it in the past, but I do not typically have a byte-compiled init.elc
file.  The auto-compile code advises `load' and `require' (which does
seem like it could present risks), however it seems so very odd to me
that user-init-file could end up with this value for any reason that
it seems like it might ultimately be an Emacs bug.

I raised it with the auto-compile maintainer (Jonas Bernoulli, CC'd)
at https://github.com/emacscollective/auto-compile/issues/33 and we
couldn't make sense of it at the time, so I'm escalating it here.

The attached bash shell recipe reproduces the issue in Emacs 29.
I can reproduce it in all of Emacs 27, 28, 29, 30 (and not 26.3 or
25.3), but this recipe uses the --init-directory option which was
added in 29.1.

(See attached script.)

The echo area in the final instance of Emacs should report the path to
compile.el.gz (and re-running the final "touch init.el && ..." command
will repeat that result each time).

If I put (debug) at the top of compile.el.gz then I get the following
backtrace, so we can see how/why compile.el is getting involved, but
it just seems very wrong for that path to be able to end up being the
user-init-file value.

Debugger entered: nil
   byte-code(...)
   compilation-mode()
   emacs-lisp-compilation-mode()
   byte-compile-log-file()
   byte-compile-from-buffer(#<buffer  *Compiler Input*>)
   byte-compile-file("/tmp/autocomp/init.el")
   auto-compile--byte-compile-file("/tmp/autocomp/init.el")
   auto-compile-on-load("/tmp/autocomp/init" nil)
   load@auto-compile("/tmp/autocomp/init" noerror nomessage)
   apply(load@auto-compile ("/tmp/autocomp/init" noerror nomessage))
   load("/tmp/autocomp/init" noerror nomessage)
   startup--load-user-init-file(#f(compiled-function () #<bytecode 
-0x54c765b3b165b77>) #f(compiled-function () #<bytecode 
-0xe2e004ca56aeafc>) t)
   command-line()
   normal-top-level()

As it seems to have started in Emacs 27, my *guess* is that it's
connected to the early-init.el system which was added in Emacs 27,
but I've not dug any further at this stage.

-Phil

In GNU Emacs 29.2 (build 2, x86_64-pc-linux-gnu, X toolkit, cairo
  version 1.16.0, Xaw scroll bars) of 2024-01-19 built on phil-lp
Repository revision: ef01b634d219bcceda17dcd61024c7a12173b88c
Repository branch: HEAD
Windowing system distributor 'The X.Org Foundation', version 
11.0.12101004
System Description: Ubuntu 22.04.4 LTS

Configured using:
  'configure --prefix=/home/phil/emacs/29.x.nc/usr/local
  --with-native-compilation=aot --with-x-toolkit=lucid --without-sound
  '--program-transform-name=s/^ctags$/ctags_emacs/''

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

Important settings:
   value of $LC_MONETARY: en_NZ.UTF-8
   value of $LC_NUMERIC: en_NZ.UTF-8
   value of $LC_TIME: en_NZ.UTF-8
   value of $LANG: en_GB.UTF-8
   value of $XMODIFIERS: @im=ibus
   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 derived epg rfc6068
epg-config gnus-util text-property-search time-date mm-decode mm-bodies
mm-encode mail-parse rfc2231 mailabbrev gmm-utils mailheader cl-loaddefs
comp comp-cstr warnings icons subr-x rx cl-seq cl-macs gv cl-extra
help-mode bytecomp byte-compile cl-lib sendmail rfc2047 rfc2045
ietf-drums mm-util mail-prsvr mail-utils 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 x-toolkit
x multi-tty make-network-process native-compile emacs)

Memory information:
((conses 16 77322 5466)
  (symbols 48 7141 0)
  (strings 32 20482 1869)
  (string-bytes 1 617241)
  (vectors 16 15637)
  (vector-slots 8 327068 13857)
  (floats 8 29 46)
  (intervals 56 248 0)
  (buffers 984 11))