Re: buffer-face-set changes the fringe, is it a bug?

[Gregory Heytings via "Emacs development discussions." <emacs-devel@gnu.org>]

>
> This is not what I see.  The left/right-fringe display property (which 
> was introduced in Emacs 22.1, btw) behaves in Emacs 22 exactly like it 
> behaves in the current codebase: if the optional FACE parameter is 
> omitted, it uses the foreground of the 'default' face and the background 
> of the 'fringe' face (because the 'fringe' face by default doesn't 
> specify the foreground).  Try this:
>
>  (set-face-attribute 'fringe nil :background "red")
>  (let ((o (make-overlay 0 1)) (s "_"))
>    (put-text-property 0 1 'display '(left-fringe question-mark) s)
>    (overlay-put o 'after-string s)
>    (set-face-foreground 'default "green"))
>

Why did you change my code, which demonstrated the problem, into another 
one which indeed does not show the problem?  Try this:

(set-face-attribute 'fringe nil :background "red" :foreground "blue")
(let ((o (make-overlay 0 1)) (s "_"))
   (put-text-property 0 1 'display '(left-fringe question-mark) s)
   (overlay-put o 'after-string s))
(progn (set-face-background 'default "yellow") (set-face-foreground 'default "red")) [1]
(face-remap-add-relative 'default '(:background "yellow" :foreground "red")) [2]

After [1] the behavior is what I expect: red on yellow in the buffer, blue 
on red in the fringe.

After [2] the behavior is *not* what I expect anymore: red on yellow in 
the buffer, red on yellow for the question mark in the fringe (the other 
parts of the fringe remain red, and other bitmaps in the fringe, e.g. 
curly arrows, remain blue on a red background).

Gregory