bug#47832: 28.0.50; define-fringe-bitmap and emacs --daemon

[Eli Zaretskii <eliz@gnu.org>]

> Date: Tue, 25 May 2021 12:44:34 +0000
> From: Gregory Heytings <gregory@heytings.org>
> cc: Lars Ingebrigtsen <larsi@gnus.org>, 47832@debbugs.gnu.org
> 
> 
> >> diff --git a/src/fringe.c b/src/fringe.c
> >> index 65c9a84..47615f5 100644
> >> --- a/src/fringe.c
> >> +++ b/src/fringe.c
> >> @@ -1776,14 +1776,15 @@ gui_init_fringe (struct redisplay_interface *rif)
> >>    for (bt = NO_FRINGE_BITMAP + 1; bt < MAX_STANDARD_FRINGE_BITMAPS; bt++)
> >>      {
> >>        struct fringe_bitmap *fb = &standard_bitmaps[bt];
> >> -      rif->define_fringe_bitmap (bt, fb->bits, fb->height, fb->width);
> >> +      if (!fringe_bitmaps[bt])
> >> +        rif->define_fringe_bitmap (bt, fb->bits, fb->height, fb->width);
> >>      }
> >>
> >>    /* Set up user-defined fringe bitmaps that might have been defined
> >>       before the frame of this kind was initialized.  This can happen
> >>       if Emacs is started as a daemon and the init files define fringe
> >>       bitmaps.  */
> >> -  for ( ; bt < max_used_fringe_bitmap; bt++)
> >> +  for (bt = NO_FRINGE_BITMAP + 1; bt < max_used_fringe_bitmap; bt++)
> >>      {
> >>        struct fringe_bitmap *fb = fringe_bitmaps[bt];
> >>        if (fb)
> >
> > Why does the second for-loop go again over the bitmaps that the first 
> > one already processed?  Or what am I missing?
> >
> 
> Each loop processes its "own" bitmaps.  In the first loop 
> define_fringe_bitmap is called only if (!fringe_bitmaps[bt]), in the 
> second loop it is called only if (fringe_bitmaps[bt]).  IOW, the first 
> loop processes the standard bitmaps that are not overridden by 
> user-defined bitmaps, and the second loop processes user-defined bitmaps.

If the standard bitmaps were overridden by user-defined ones, why do
we need to set those overriding user-defined bitmaps once again?