bug#32921: emacsclient obeys Xresources even when launched with -nw

[Po Lu via "Bug reports for GNU Emacs, the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>]

Eli Zaretskii <eliz@gnu.org> writes:

> We may be miscommunicating.  The offending code in x-win.el is called
> at startup, only once, and sets up default-frame-alist for all the
> future frames, including those on displays this Emacs session did not
> yet open and knows nothing about.  How would you define
> default-frame-alist that is specific to those as-yet-unknown displays?

I would leave it empty.

> And if you are saying that the code in x-win.el should only affect the
> display on which Emacs was started, then that would be an even more
> seriously breaking change.  Why should we assume that the user
> intended his/her X resources to be only honored on the (random)
> display where Emacs shows its first frame?  The files ~/.Xresources
> and ~/.Xdefaults are not specific to any display, AFAIU, they are
> global for the user.  Right?

Emacs _never_ honored any other X resource that happened to be on the
first display for every display, and I have a feeling this code was a
mistake left over from the refactoring of `x-win.el' when multi-TTY was
developed.

Emacs, like all other X programs, takes resources from several different
sources:

  - The system's locale-specific X resources.  This is normally empty on
    modern systems.

  - The user's personal X resource files for Emacs.  This is also mostly
    empty on modern systems.

  - The user's X defaults that were loaded into the X server.  Only if
    the no X resources were loaded into the X server will Emacs try to
    load them itself from ~/.Xdefaults.

  - The environment defaults.  Also empty on modern systems.

This is why X resources are typically specific to each X server, which
is also why Emacs keeps a different resource database for each display
connection, and does not try to apply resources (other than
`reverseVideo') from one display connection to another.