bug#72294: 29.2; Emacs --init-directory=... puts user-init-file elsewhere

[Robert Pluim]

>>>>> On Thu, 25 Jul 2024 15:59:45 -0400, Sean Devlin <spd@toadstyle.org> said:

    Sean> Hi,
    >> I don't think this is a bug.

    Sean> Fair enough.

    >> May I ask why you needed to use this option?  It should not be
    >> generally needed.

    Sean> Lately, I run Emacs from the emacs-30 branch with some local tweaks. I
    Sean> found a bug in Org, and I was trying to reproduce it in a stable 
version
    Sean> of Emacs with default configuration. The bug is in Org 9.7+, which is
    Sean> newer than what ships in Emacs 29.

    Sean> Since I knew I would need to install a package, I checked the manual 
for
    Sean> the command-line flags to specify the user-emacs-directory, and I 
found
    Sean> the --init-directory option. I opened an instance of Emacs 29.2 with
    Sean> --init-directory=/tmp/bug, and I installed Org via ELPA.

The emacs info file says

    ‘--init-directory’
         Specify the directory to use when looking for the Emacs init files.

and '.emacs' is an Emacs init file, so I guess the confusion is
understandable. Maybe we should add "(except '.emacs')" to that
statement.

    Sean> Then, for an unrelated task, I opened an instance of my main Emacs
    Sean> installation, and I was surprised to see it load without any of my
    Sean> configuration. I discovered the Emacs 29 instance had written a file 
to
    Sean> ~/.emacs, shadowing my own configuration in ~/.emacs.d/init.el. That 
it
    Sean> wrote the user-init-file outside the user-emacs-directory I specified
    Sean> was surprising to me.

    HOME=/tmp/emacs emacs

is how I do that kind of testing.

Robert
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