bug#54961: 28.1; info-display-manual completions issues

[Alan Third]

On Tue, Apr 19, 2022 at 07:55:30PM +0300, Eli Zaretskii wrote:
> > on emacs -Q (on mac)
> > 
> > Info-default-directory-list
> > ("/Applications/GnuEmacs.app/Contents/Resources/info/" 
> > "/usr/local/share/info/" "/usr/share/info/")
> > 
> > after running C-h i, Info-directory-list is the same
> > ("/Applications/GnuEmacs.app/Contents/Resources/info/" 
> > "/usr/local/share/info/" "/usr/share/info/")
<snip>
> But then info-initialize, which is supposed to implement the above,
> deviates from that behavior on macOS, with this commentary:
> 
>       ;; For a self-contained (ie relocatable) NS build, AFAICS we
>       ;; always want the included info directory to be at the head of
>       ;; the search path, unless it's already in INFOPATH somewhere.
>       ;; It's at the head of Info-default-directory-list,
>       ;; but there's no way to get it at the head of Info-directory-list
>       ;; except by doing it here.
> 
> I cannot say I understand this reasoning, and neither do I understand
> whether this explains what you see in your case (because I don't know
> what is meant by "self-contained i.e. relocatable NS build".

I'm not sure what the reasoning is either.

The self-contained build is where all Emacs's files are installed in a
special directory, in this case "/Applications/GnuEmacs.app" which can
be placed anywhere on the filesystem and run from the GUI.

My uneducated guess is that it's possible to have a "UNIX" style
install already on a machine, which might be in /usr and then want to
run the self-contained version and not pick up the files in /usr
before the self-contained version's files.

I've no idea if that's plausible.

It looks like Glen's included a couple of links about why this was
done in change eb7afdaddc286b57253cf0cd643b2ea594fb130c.
-- 
Alan Third