Package: emacs;
Reported by: lompik <at> voila.fr
Date: Wed, 24 Sep 2014 13:40:02 UTC
Severity: normal
Found in version 24.4.50
Done: Eli Zaretskii <eliz <at> gnu.org>
Bug is archived. No further changes may be made.
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From: Eli Zaretskii <eliz <at> gnu.org> To: lompik <at> voila.fr Cc: 18545 <at> debbugs.gnu.org Subject: bug#18545: 24.4.50: Bug - forward-line inside with-selected-window Date: Mon, 29 Sep 2014 16:47:31 +0300
> Date: Mon, 29 Sep 2014 09:16:22 +0300
> From: Eli Zaretskii <eliz <at> gnu.org>
> Cc: 18545 <at> debbugs.gnu.org
>
> > Date: Mon, 29 Sep 2014 02:31:04 +0200 (CEST)
> > From: lompik <at> voila.fr
> > Cc: 18545 <at> debbugs.gnu.org
> >
> > C-x C-f -> in a folder with lots of files
> > [tab]x2 -> open completion buffer
> > C-! -> modify completion buffer
> > C-h k a -> Show help for letter "a" (Important ! skipping this results in no bug )
> > C-` until bottom of *Completions* buffer -> no scrolling,
> >
> >
> > I have applied the 3 patches that you supplied on emacs bzr revno 117517. I have tested this on 24.3.93 as well.
>
> Thanks. This is indeed very similar to what Martin presented,
> i.e. forward-line moves point outside of the window, and then
> redisplay returns point back into the view. But since the change that
> fixed Martin's case doesn't fix this one, I guess some other place in
> the code is setting the force_start flag of the window.
>
> I will look into this.
It's a god-awful mess. In this use case, we enter that code not
because of the force_start flag, but because of the frame's
frozen_window_starts flag. That flag is set when we resize the
minibuffer window, and it currently acts almost like the force_start
flag. (There's a function window_frozen_p, which attempts to exempt
some special windows from this "frozen-start" state, but it cannot
handle this complicated case, because by the time redisplay kicks in,
the fact that *Completions* was at some point displayed by the
selected window is long forgotten, and its window is now just like any
other one.)
The best solution I can propose is in the patch below, which is a
cumulative patch against the emacs-24 branch, and is supposed to fix
all of these problems. It fixes this last problem by treating the
frozen_window_starts flag as advisory, i.e. like we treat the
optional_new_start flag of a window.
Please test it. I will commit it later today (to get it into the next
pretest).
=== modified file 'src/window.c'
--- src/window.c 2014-09-11 08:47:34 +0000
+++ src/window.c 2014-09-29 06:03:36 +0000
@@ -5897,6 +5897,8 @@ and redisplay normally--don't erase and
w->start_at_line_beg = (bytepos == BEGV_BYTE ||
FETCH_BYTE (bytepos - 1) == '\n');
+ wset_redisplay (w);
+
set_buffer_internal (obuf);
return Qnil;
}
=== modified file 'src/xdisp.c'
--- src/xdisp.c 2014-09-18 15:10:33 +0000
+++ src/xdisp.c 2014-09-29 13:13:42 +0000
@@ -15027,6 +15027,10 @@ run_window_scroll_functions (Lisp_Object
If FORCE_P is non-zero, return 0 even if partial visible cursor row
is higher than window.
+ If CURRENT_MATRIX_P is non-zero, use the information from the
+ window's current glyph matrix; otherwise uze the desired glyph
+ matrix.
+
A value of 0 means the caller should do scrolling
as if point had gone off the screen. */
@@ -16136,26 +16140,47 @@ redisplay_window (Lisp_Object window, bo
/* If someone specified a new starting point but did not insist,
check whether it can be used. */
- if (w->optional_new_start
+ if ((w->optional_new_start || window_frozen_p (w))
&& CHARPOS (startp) >= BEGV
&& CHARPOS (startp) <= ZV)
{
+ ptrdiff_t it_charpos;
+
w->optional_new_start = 0;
start_display (&it, w, startp);
move_it_to (&it, PT, 0, it.last_visible_y, -1,
MOVE_TO_POS | MOVE_TO_X | MOVE_TO_Y);
- if (IT_CHARPOS (it) == PT)
- w->force_start = 1;
- /* IT may overshoot PT if text at PT is invisible. */
- else if (IT_CHARPOS (it) > PT && CHARPOS (startp) <= PT)
- w->force_start = 1;
+ /* Record IT's position now, since line_bottom_y might change
+ that. */
+ it_charpos = IT_CHARPOS (it);
+ /* Make sure we set the force_start flag only if the cursor row
+ will be fully visible. Otherwise, the code under force_start
+ label below will try to move point back into view, which is
+ not what the code which sets optional_new_start wants. */
+ if (line_bottom_y (&it) < it.last_visible_y && !w->force_start)
+ {
+ if (it_charpos == PT)
+ w->force_start = 1;
+ /* IT may overshoot PT if text at PT is invisible. */
+ else if (it_charpos > PT && CHARPOS (startp) <= PT)
+ w->force_start = 1;
+#ifdef GLYPH_DEBUG
+ if (w->force_start)
+ {
+ if (window_frozen_p (w))
+ debug_method_add (w, "set force_start from frozen window start");
+ else
+ debug_method_add (w, "set force_start from optional_new_start");
+ }
+#endif
+ }
}
force_start:
/* Handle case where place to start displaying has been specified,
unless the specified location is outside the accessible range. */
- if (w->force_start || window_frozen_p (w))
+ if (w->force_start)
{
/* We set this later on if we have to adjust point. */
int new_vpos = -1;
@@ -16200,7 +16225,7 @@ redisplay_window (Lisp_Object window, bo
goto need_larger_matrices;
}
- if (w->cursor.vpos < 0 && !window_frozen_p (w))
+ if (w->cursor.vpos < 0)
{
/* If point does not appear, try to move point so it does
appear. The desired matrix has been built above, so we
@@ -16293,6 +16318,11 @@ redisplay_window (Lisp_Object window, bo
}
*/
}
+ if (w->cursor.vpos < 0 || !cursor_row_fully_visible_p (w, 0, 0))
+ {
+ clear_glyph_matrix (w->desired_matrix);
+ goto try_to_scroll;
+ }
#ifdef GLYPH_DEBUG
debug_method_add (w, "forced window start");
@@ -16357,7 +16387,8 @@ redisplay_window (Lisp_Object window, bo
|| CHARPOS (startp) == BEGV
|| !window_outdated (w)))
{
- int d1, d2, d3, d4, d5, d6;
+ int d1, d2, d5, d6;
+ int rtop, rbot;
/* If first window line is a continuation line, and window start
is inside the modified region, but the first change is before
@@ -16386,10 +16417,14 @@ redisplay_window (Lisp_Object window, bo
doing so will move point from its correct position
instead of scrolling the window to bring point into view.
See bug#9324. */
- && pos_visible_p (w, PT, &d1, &d2, &d3, &d4, &d5, &d6))
+ && pos_visible_p (w, PT, &d1, &d2, &rtop, &rbot, &d5, &d6)
+ && rtop == 0 && rbot == 0)
{
w->force_start = 1;
SET_TEXT_POS_FROM_MARKER (startp, w->start);
+#ifdef GLYPH_DEBUG
+ debug_method_add (w, "recomputed window start in continuation line");
+#endif
goto force_start;
}
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