1 files changed, 294 insertions, 115 deletions

diff --git a/src/window.c b/src/window.c
index 54e17be..9ffca77 100644
--- a/src/window.c
+++ b/src/window.c
@@ -17,8 +17,8 @@ static void frame_setheight(frame_T *curfrp, int height);
 static void frame_setwidth(frame_T *curfrp, int width);
 static void win_exchange(long);
 static void win_rotate(int, int);
-static void win_totop(int size, int flags);
 static void win_equal_rec(win_T *next_curwin, int current, frame_T *topfr, int dir, int col, int row, int width, int height);
+static void trigger_winnewpre(void);
 static void trigger_winclosed(win_T *win);
 static win_T *win_free_mem(win_T *win, int *dirp, tabpage_T *tp);
 static frame_T *win_altframe(win_T *win, tabpage_T *tp);
@@ -53,8 +53,10 @@ static void win_goto_ver(int up, long count);
 static void win_goto_hor(int left, long count);
 static void frame_add_height(frame_T *frp, int n);
 static void last_status_rec(frame_T *fr, int statusline);
+static void frame_flatten(frame_T *frp);
+static void winframe_restore(win_T *wp, int dir, frame_T *unflat_altfr);
 
-static void make_snapshot_rec(frame_T *fr, frame_T **frp);
+static int make_snapshot_rec(frame_T *fr, frame_T **frp);
 static void clear_snapshot(tabpage_T *tp, int idx);
 static void clear_snapshot_rec(frame_T *fr);
 static int check_snapshot_rec(frame_T *sn, frame_T *fr);
@@ -157,6 +159,37 @@ log_frame_layout(frame_T *frame)
 #endif
 
 /*
+ * Check if the current window is allowed to move to a different buffer.
+ * If the window has 'winfixbuf', this function will return FALSE.
+ */
+    int
+check_can_set_curbuf_disabled(void)
+{
+    if (curwin->w_p_wfb)
+    {
+	emsg(_(e_winfixbuf_cannot_go_to_buffer));
+	return FALSE;
+    }
+    return TRUE;
+}
+
+/*
+ * Check if the current window is allowed to move to a different buffer.
+ * If the window has 'winfixbuf', then forceit must be TRUE or this function
+ * will return FALSE.
+ */
+    int
+check_can_set_curbuf_forceit(int forceit)
+{
+    if (!forceit && curwin->w_p_wfb)
+    {
+	emsg(_(e_winfixbuf_cannot_go_to_buffer));
+	return FALSE;
+    }
+    return TRUE;
+}
+
+/*
  * Return the current window, unless in the cmdline window and "prevwin" is
  * set, then return "prevwin".
  */
@@ -493,9 +526,15 @@ newwindow:
     case 'H':
     case 'L':
 		CHECK_CMDWIN;
-		win_totop((int)Prenum,
-			((nchar == 'H' || nchar == 'L') ? WSP_VERT : 0)
-			| ((nchar == 'H' || nchar == 'K') ? WSP_TOP : WSP_BOT));
+		if (ONE_WINDOW)
+		    beep_flush();
+		else
+		{
+		    int dir = ((nchar == 'H' || nchar == 'L') ? WSP_VERT : 0)
+			 | ((nchar == 'H' || nchar == 'K') ? WSP_TOP : WSP_BOT);
+
+		    (void)win_splitmove(curwin, (int)Prenum, dir);
+		}
 		break;
 
 // make all windows the same width and/or height
@@ -659,7 +698,7 @@ wingotofile:
 
 		find_pattern_in_path(ptr, 0, len, TRUE,
 			Prenum == 0 ? TRUE : FALSE, type,
-			Prenum1, ACTION_SPLIT, (linenr_T)1, (linenr_T)MAXLNUM);
+			Prenum1, ACTION_SPLIT, (linenr_T)1, (linenr_T)MAXLNUM, FALSE);
 		vim_free(ptr);
 		curwin->w_set_curswant = TRUE;
 		break;
@@ -857,18 +896,18 @@ cmd_with_count(
 }
 
 /*
- * If "split_disallowed" is set give an error and return FAIL.
- * Otherwise return OK.
+ * If "split_disallowed" is set, or "wp"'s buffer is closing, give an error and
+ * return FAIL.  Otherwise return OK.
  */
-    static int
-check_split_disallowed(void)
+    int
+check_split_disallowed(win_T *wp)
 {
     if (split_disallowed > 0)
     {
 	emsg(_(e_cant_split_window_while_closing_another));
 	return FAIL;
     }
-    if (curwin->w_buffer->b_locked_split)
+    if (wp->w_buffer->b_locked_split)
     {
 	emsg(_(e_cannot_split_window_when_closing_buffer));
 	return FAIL;
@@ -897,7 +936,7 @@ win_split(int size, int flags)
     if (ERROR_IF_ANY_POPUP_WINDOW)
 	return FAIL;
 
-    if (check_split_disallowed() == FAIL)
+    if (check_split_disallowed(curwin) == FAIL)
 	return FAIL;
 
     // When the ":tab" modifier was used open a new tab page instead.
@@ -919,13 +958,18 @@ win_split(int size, int flags)
     else
 	clear_snapshot(curtab, SNAP_HELP_IDX);
 
-    return win_split_ins(size, flags, NULL, 0);
+    return win_split_ins(size, flags, NULL, 0, NULL);
 }
 
 /*
  * When "new_wp" is NULL: split the current window in two.
  * When "new_wp" is not NULL: insert this window at the far
  * top/left/right/bottom.
+ * When "to_flatten" is not NULL: flatten this frame before reorganising frames;
+ * remains unflattened on failure.
+ *
+ * On failure, if "new_wp" was not NULL, no changes will have been made to the
+ * window layout or sizes.
  * Return FAIL for failure, OK otherwise.
  */
     int
@@ -933,7 +977,8 @@ win_split_ins(
     int		size,
     int		flags,
     win_T	*new_wp,
-    int		dir)
+    int		dir,
+    frame_T	*to_flatten)
 {
     win_T	*wp = new_wp;
     win_T	*oldwin;
@@ -955,6 +1000,9 @@ win_split_ins(
     // Do not redraw here, curwin->w_buffer may be invalid.
     ++RedrawingDisabled;
 
+    if (new_wp == NULL)
+	trigger_winnewpre();
+
     if (flags & WSP_TOP)
 	oldwin = firstwin;
     else if (flags & WSP_BOT)
@@ -965,7 +1013,7 @@ win_split_ins(
     // add a status line when p_ls == 1 and splitting the first window
     if (ONE_WINDOW && p_ls == 1 && oldwin->w_status_height == 0)
     {
-	if (VISIBLE_HEIGHT(oldwin) <= p_wmh && new_wp == NULL)
+	if (!(flags & WSP_FORCE_ROOM) && VISIBLE_HEIGHT(oldwin) <= p_wmh)
 	{
 	    emsg(_(e_not_enough_room));
 	    goto theend;
@@ -1023,7 +1071,7 @@ win_split_ins(
 	    available = oldwin->w_frame->fr_width;
 	    needed += minwidth;
 	}
-	if (available < needed && new_wp == NULL)
+	if (!(flags & WSP_FORCE_ROOM) && available < needed)
 	{
 	    emsg(_(e_not_enough_room));
 	    goto theend;
@@ -1106,7 +1154,7 @@ win_split_ins(
 	    available = oldwin->w_frame->fr_height;
 	    needed += minheight;
 	}
-	if (available < needed && new_wp == NULL)
+	if (!(flags & WSP_FORCE_ROOM) && available < needed)
 	{
 	    emsg(_(e_not_enough_room));
 	    goto theend;
@@ -1205,6 +1253,10 @@ win_split_ins(
 	win_init(wp, curwin, flags);
     }
 
+    // Going to reorganize frames now, make sure they're flat.
+    if (to_flatten != NULL)
+	frame_flatten(to_flatten);
+
     /*
      * Reorganise the tree of frames to insert the new window.
      */
@@ -1433,7 +1485,7 @@ win_split_ins(
     /*
      * make the new window the current window
      */
-    (void)win_enter_ext(wp, WEE_TRIGGER_NEW_AUTOCMDS
+    (void)win_enter_ext(wp, (new_wp == NULL ? WEE_TRIGGER_NEW_AUTOCMDS : 0)
 		    | WEE_TRIGGER_ENTER_AUTOCMDS | WEE_TRIGGER_LEAVE_AUTOCMDS);
     if (flags & WSP_VERT)
 	p_wiw = i;
@@ -1897,35 +1949,51 @@ win_rotate(int upwards, int count)
 }
 
 /*
- * Move the current window to the very top/bottom/left/right of the screen.
+ * Move "wp" into a new split in a given direction, possibly relative to the
+ * current window.
+ * "wp" must be valid in the current tabpage.
+ * Returns FAIL for failure, OK otherwise.
  */
-    static void
-win_totop(int size, int flags)
+    int
+win_splitmove(win_T *wp, int size, int flags)
 {
     int		dir;
-    int		height = curwin->w_height;
+    int		height = wp->w_height;
+    frame_T	*unflat_altfr;
 
     if (ONE_WINDOW)
-    {
-	beep_flush();
-	return;
-    }
-    if (check_split_disallowed() == FAIL)
-	return;
+	return OK;	// nothing to do
+    if (check_split_disallowed(wp) == FAIL)
+	return FAIL;
 
-    // Remove the window and frame from the tree of frames.
-    (void)winframe_remove(curwin, &dir, NULL);
-    win_remove(curwin, NULL);
+    // Remove the window and frame from the tree of frames.  Don't flatten any
+    // frames yet so we can restore things if win_split_ins fails.
+    winframe_remove(wp, &dir, NULL, &unflat_altfr);
+    win_remove(wp, NULL);
     last_status(FALSE);	    // may need to remove last status line
     (void)win_comp_pos();   // recompute window positions
 
-    // Split a window on the desired side and put the window there.
-    (void)win_split_ins(size, flags, curwin, dir);
-    if (!(flags & WSP_VERT))
+    // Split a window on the desired side and put "wp" there.
+    if (win_split_ins(size, flags, wp, dir, unflat_altfr) == FAIL)
+    {
+	// win_split_ins doesn't change sizes or layout if it fails to insert an
+	// existing window, so just undo winframe_remove.
+	winframe_restore(wp, dir, unflat_altfr);
+	win_append(wp->w_prev, wp);
+	return FAIL;
+    }
+
+    // If splitting horizontally, try to preserve height.
+    // Note that win_split_ins autocommands may have immediately closed "wp"!
+    if (size == 0 && !(flags & WSP_VERT) && win_valid(wp))
     {
-	win_setheight(height);
+	win_setheight_win(height, wp);
 	if (p_ea)
-	    win_equal(curwin, TRUE, 'v');
+	{
+	    // Equalize windows.  Note that win_split_ins autocommands may have
+	    // made a window other than "wp" current.
+	    win_equal(curwin, curwin == wp, 'v');
+	}
     }
 
 #if defined(FEAT_GUI)
@@ -1933,6 +2001,7 @@ win_totop(int size, int flags)
     // scrollbars.  Have to update them anyway.
     gui_may_update_scrollbars();
 #endif
+    return OK;
 }
 
 /*
@@ -2362,7 +2431,7 @@ leaving_window(win_T *win)
     // When leaving the window (or closing the window) was done from a
     // callback we need to break out of the Insert mode loop and restart Insert
     // mode when entering the window again.
-    if (State & MODE_INSERT)
+    if ((State & MODE_INSERT) && !stop_insert_mode)
     {
 	stop_insert_mode = TRUE;
 	if (win->w_buffer->b_prompt_insert == NUL)
@@ -2485,7 +2554,7 @@ close_windows(
  * "aucmd_win[]").
  * Returns FALSE if there is a window, possibly in another tab page.
  */
-    static int
+    int
 last_window(void)
 {
     return (one_window() && first_tabpage->tp_next == NULL);
@@ -2515,7 +2584,7 @@ one_window(void)
 
 /*
  * Close the possibly last window in a tab page.
- * Returns TRUE when the window was closed already.
+ * Return FALSE if there are other windows and nothing is done, TRUE otherwise.
  */
     static int
 close_last_window_tabpage(
@@ -2653,7 +2722,7 @@ win_close(win_T *win, int free_buf)
     // and then close the window and the tab page to avoid that curwin and
     // curtab are invalid while we are freeing memory.
     if (close_last_window_tabpage(win, free_buf, prev_curtab))
-      return FAIL;
+	return FAIL;
 
     // When closing the help window, try restoring a snapshot after closing
     // the window.  Otherwise clear the snapshot, it's now invalid.
@@ -2726,9 +2795,11 @@ win_close(win_T *win, int free_buf)
 
     win_close_buffer(win, free_buf ? DOBUF_UNLOAD : 0, TRUE);
 
-    if (only_one_window() && win_valid(win) && win->w_buffer == NULL
-	    && (last_window() || curtab != prev_curtab
-		|| close_last_window_tabpage(win, free_buf, prev_curtab)))
+    if (win_valid(win) && win->w_buffer == NULL
+#if defined(FEAT_PROP_POPUP)
+	    && !popup_is_popup(win)
+#endif
+	    && last_window())
     {
 	// Autocommands have closed all windows, quit now.  Restore
 	// curwin->w_buffer, otherwise writing viminfo may fail.
@@ -2742,10 +2813,7 @@ win_close(win_T *win, int free_buf)
 						      && win->w_buffer == NULL)
     {
 	// Need to close the window anyway, since the buffer is NULL.
-	// Don't trigger autocmds with a NULL buffer.
-	block_autocmds();
 	win_close_othertab(win, FALSE, prev_curtab);
-	unblock_autocmds();
 	return FAIL;
     }
 
@@ -2887,6 +2955,14 @@ win_close(win_T *win, int free_buf)
 }
 
     static void
+trigger_winnewpre(void)
+{
+    window_layout_lock();
+    apply_autocmds(EVENT_WINNEWPRE, NULL, NULL, FALSE, NULL);
+    window_layout_unlock();
+}
+
+    static void
 trigger_winclosed(win_T *win)
 {
     static int	recursive = FALSE;
@@ -3274,10 +3350,15 @@ win_close_othertab(win_T *win, int free_buf, tabpage_T *tp)
 	return; // window is already being closed
 
     // Trigger WinClosed just before starting to free window-related resources.
-    trigger_winclosed(win);
-    // autocmd may have freed the window already.
-    if (!win_valid_any_tab(win))
-	return;
+    // If the buffer is NULL, it isn't safe to trigger autocommands,
+    // and win_close() should have already triggered WinClosed.
+    if (win->w_buffer != NULL)
+    {
+	trigger_winclosed(win);
+	// autocmd may have freed the window already.
+	if (!win_valid_any_tab(win))
+	    return;
+    }
 
     if (win->w_buffer != NULL)
 	// Close the link to the buffer.
@@ -3355,7 +3436,7 @@ win_free_mem(
 
     // Remove the window and its frame from the tree of frames.
     frp = win->w_frame;
-    wp = winframe_remove(win, dirp, tp);
+    wp = winframe_remove(win, dirp, tp, NULL);
     vim_free(frp);
     win_free(win, tp);
 
@@ -3375,6 +3456,8 @@ win_free_all(void)
 
     // avoid an error for switching tabpage with the cmdline window open
     cmdwin_type = 0;
+    cmdwin_buf = NULL;
+    cmdwin_win = NULL;
 
     while (first_tabpage->tp_next != NULL)
 	tabpage_close(TRUE);
@@ -3403,11 +3486,14 @@ win_free_all(void)
 winframe_remove(
     win_T	*win,
     int		*dirp UNUSED,	// set to 'v' or 'h' for direction if 'ea'
-    tabpage_T	*tp)		// tab page "win" is in, NULL for current
+    tabpage_T	*tp,		// tab page "win" is in, NULL for current
+    frame_T	**unflat_altfr)	// if not NULL, set to pointer of frame that got
+				// the space, and it is not flattened
 {
     frame_T	*frp, *frp2, *frp3;
     frame_T	*frp_close = win->w_frame;
     win_T	*wp;
+    int		row, col;
 
     /*
      * If there is only one window there is nothing to remove.
@@ -3415,6 +3501,12 @@ winframe_remove(
     if (tp == NULL ? ONE_WINDOW : tp->tp_firstwin == tp->tp_lastwin)
 	return NULL;
 
+    // Save the position of the containing frame (which will also contain the
+    // altframe) before we remove anything, to recompute window positions later.
+    wp = frame2win(frp_close->fr_parent);
+    row = wp->w_winrow;
+    col = wp->w_wincol;
+
     /*
      * Remove the window from its frame.
      */
@@ -3458,7 +3550,7 @@ winframe_remove(
 	    }
 	}
 	frame_new_height(frp2, frp2->fr_height + frp_close->fr_height,
-			    frp2 == frp_close->fr_next ? TRUE : FALSE, FALSE);
+			    frp2 == frp_close->fr_next, FALSE);
 	*dirp = 'v';
     }
     else
@@ -3495,64 +3587,127 @@ winframe_remove(
 	    }
 	}
 	frame_new_width(frp2, frp2->fr_width + frp_close->fr_width,
-			    frp2 == frp_close->fr_next ? TRUE : FALSE, FALSE);
+			    frp2 == frp_close->fr_next, FALSE);
 	*dirp = 'h';
     }
 
-    // If rows/columns go to a window below/right its positions need to be
-    // updated.  Can only be done after the sizes have been updated.
-    if (frp2 == frp_close->fr_next)
-    {
-	int row = win->w_winrow;
-	int col = win->w_wincol;
+    // If the altframe wasn't adjacent and left/above, resizing it will have
+    // changed window positions within the parent frame.  Recompute them.
+    if (frp2 != frp_close->fr_prev)
+	frame_comp_pos(frp_close->fr_parent, &row, &col);
 
-	frame_comp_pos(frp2, &row, &col);
-    }
+    if (unflat_altfr == NULL)
+	frame_flatten(frp2);
+    else
+	*unflat_altfr = frp2;
 
-    if (frp2->fr_next == NULL && frp2->fr_prev == NULL)
-    {
-	// There is no other frame in this list, move its info to the parent
-	// and remove it.
-	frp2->fr_parent->fr_layout = frp2->fr_layout;
-	frp2->fr_parent->fr_child = frp2->fr_child;
-	FOR_ALL_FRAMES(frp, frp2->fr_child)
-	    frp->fr_parent = frp2->fr_parent;
-	frp2->fr_parent->fr_win = frp2->fr_win;
-	if (frp2->fr_win != NULL)
-	    frp2->fr_win->w_frame = frp2->fr_parent;
-	frp = frp2->fr_parent;
-	if (topframe->fr_child == frp2)
-	    topframe->fr_child = frp;
-	vim_free(frp2);
+    return wp;
+}
+
+/*
+ * Flatten "frp" into its parent frame if it's the only child, also merging its
+ * list with the grandparent if they share the same layout.
+ * Frees "frp" if flattened; also "frp->fr_parent" if it has the same layout.
+ */
+    static void
+frame_flatten(frame_T *frp)
+{
+    frame_T	*frp2, *frp3;
+
+    if (frp->fr_next != NULL || frp->fr_prev != NULL)
+	return;
 
-	frp2 = frp->fr_parent;
-	if (frp2 != NULL && frp2->fr_layout == frp->fr_layout)
+    // There is no other frame in this list, move its info to the parent
+    // and remove it.
+    frp->fr_parent->fr_layout = frp->fr_layout;
+    frp->fr_parent->fr_child = frp->fr_child;
+    FOR_ALL_FRAMES(frp2, frp->fr_child)
+	frp2->fr_parent = frp->fr_parent;
+    frp->fr_parent->fr_win = frp->fr_win;
+    if (frp->fr_win != NULL)
+	frp->fr_win->w_frame = frp->fr_parent;
+    frp2 = frp->fr_parent;
+    if (topframe->fr_child == frp)
+	topframe->fr_child = frp2;
+    vim_free(frp);
+
+    frp = frp2->fr_parent;
+    if (frp != NULL && frp->fr_layout == frp2->fr_layout)
+    {
+	// The frame above the parent has the same layout, have to merge
+	// the frames into this list.
+	if (frp->fr_child == frp2)
+	    frp->fr_child = frp2->fr_child;
+	frp2->fr_child->fr_prev = frp2->fr_prev;
+	if (frp2->fr_prev != NULL)
+	    frp2->fr_prev->fr_next = frp2->fr_child;
+	for (frp3 = frp2->fr_child; ; frp3 = frp3->fr_next)
 	{
-	    // The frame above the parent has the same layout, have to merge
-	    // the frames into this list.
-	    if (frp2->fr_child == frp)
-		frp2->fr_child = frp->fr_child;
-	    frp->fr_child->fr_prev = frp->fr_prev;
-	    if (frp->fr_prev != NULL)
-		frp->fr_prev->fr_next = frp->fr_child;
-	    for (frp3 = frp->fr_child; ; frp3 = frp3->fr_next)
+	    frp3->fr_parent = frp;
+	    if (frp3->fr_next == NULL)
 	    {
-		frp3->fr_parent = frp2;
-		if (frp3->fr_next == NULL)
-		{
-		    frp3->fr_next = frp->fr_next;
-		    if (frp->fr_next != NULL)
-			frp->fr_next->fr_prev = frp3;
-		    break;
-		}
+		frp3->fr_next = frp2->fr_next;
+		if (frp2->fr_next != NULL)
+		    frp2->fr_next->fr_prev = frp3;
+		break;
 	    }
-	    if (topframe->fr_child == frp)
-		topframe->fr_child = frp2;
-	    vim_free(frp);
 	}
+	if (topframe->fr_child == frp2)
+	    topframe->fr_child = frp;
+	vim_free(frp2);
     }
+}
 
-    return wp;
+/*
+ * Undo changes from a prior call to winframe_remove, also restoring lost
+ * vertical separators and statuslines, and changed window positions for
+ * windows within "unflat_altfr".
+ * Caller must ensure no other changes were made to the layout or window sizes!
+ */
+    static void
+winframe_restore(win_T *wp, int dir, frame_T *unflat_altfr)
+{
+    frame_T	*frp = wp->w_frame;
+
+    // Put "wp"'s frame back where it was.
+    if (frp->fr_prev != NULL)
+	frame_append(frp->fr_prev, frp);
+    else
+	frame_insert(frp->fr_next, frp);
+
+    // Vertical separators to the left may have been lost.  Restore them.
+    if (wp->w_vsep_width == 0
+	    && frp->fr_parent->fr_layout == FR_ROW && frp->fr_prev != NULL)
+	frame_add_vsep(frp->fr_prev);
+
+    // Statuslines above may have been lost.  Restore them.
+    if (wp->w_status_height == 0
+	    && frp->fr_parent->fr_layout == FR_COL && frp->fr_prev != NULL)
+	frame_add_statusline(frp->fr_prev);
+
+    // Restore the lost room that was redistributed to the altframe.  Also
+    // adjusts window sizes to fit restored statuslines/separators, if needed.
+    if (dir == 'v')
+    {
+	frame_new_height(unflat_altfr, unflat_altfr->fr_height - frp->fr_height,
+		unflat_altfr == frp->fr_next, FALSE);
+    }
+    else if (dir == 'h')
+    {
+	frame_new_width(unflat_altfr, unflat_altfr->fr_width - frp->fr_width,
+		unflat_altfr == frp->fr_next, FALSE);
+    }
+
+    // Recompute window positions within the parent frame to restore them.
+    // Positions were unchanged if the altframe was adjacent and left/above.
+    if (unflat_altfr != frp->fr_prev)
+    {
+	win_T	*topleft = frame2win(frp->fr_parent);
+	int	row = topleft->w_winrow;
+	int	col = topleft->w_wincol;
+
+	frame_comp_pos(frp->fr_parent, &row, &col);
+    }
 }
 
 /*
@@ -4475,6 +4630,9 @@ win_new_tabpage(int after)
 
     newtp->tp_localdir = (tp->tp_localdir == NULL)
 				    ? NULL : vim_strsave(tp->tp_localdir);
+
+    trigger_winnewpre();
+
     // Create a new empty window.
     if (win_alloc_firstwin(tp->tp_curwin) == OK)
     {
@@ -5381,15 +5539,11 @@ win_enter_ext(win_T *wp, int flags)
     // may have to copy the buffer options when 'cpo' contains 'S'
     if (wp->w_buffer != curbuf)
 	buf_copy_options(wp->w_buffer, BCO_ENTER | BCO_NOHELP);
-
     if (curwin_invalid == 0)
     {
 	prevwin = curwin;	// remember for CTRL-W p
 	curwin->w_redr_status = TRUE;
     }
-    else if (wp == prevwin)
-	prevwin = NULL;		// don't want it to be the new curwin
-
     curwin = wp;
     curbuf = wp->w_buffer;
     check_cursor();
@@ -7131,17 +7285,17 @@ command_height(void)
 
     // If the space for the command line is already more than 'cmdheight' there
     // is nothing to do (window size must have decreased).
+    // Note: this makes curtab->tp_ch_used unreliable
     if (p_ch > old_p_ch && cmdline_row <= Rows - p_ch)
 	return;
 
     // Update cmdline_row to what it should be: just below the last window.
     cmdline_row = topframe->fr_height + tabline_height();
 
-    // If cmdline_row is smaller than what it is supposed to be for 'cmdheight'
-    // then set old_p_ch to what it would be, so that the windows get resized
+    // old_p_ch may be unreliable, because of the early return above, so
+    // set old_p_ch to what it would be, so that the windows get resized
     // properly for the new value.
-    if (cmdline_row < Rows - p_ch)
-	old_p_ch = Rows - cmdline_row;
+    old_p_ch = Rows - cmdline_row;
 
     // Find bottom frame with width of screen.
     frp = lastwin->w_frame;
@@ -7482,29 +7636,42 @@ reset_lnums(void)
 /*
  * Create a snapshot of the current frame sizes.
  * "idx" is SNAP_HELP_IDX or SNAP_AUCMD_IDX.
+ * Return FAIL if out of memory, OK otherwise.
  */
-    void
+    int
 make_snapshot(int idx)
 {
     clear_snapshot(curtab, idx);
-    make_snapshot_rec(topframe, &curtab->tp_snapshot[idx]);
+    if (make_snapshot_rec(topframe, &curtab->tp_snapshot[idx]) == FAIL)
+    {
+	clear_snapshot(curtab, idx);
+	return FAIL;
+    }
+    return OK;
 }
 
-    static void
+    static int
 make_snapshot_rec(frame_T *fr, frame_T **frp)
 {
     *frp = ALLOC_CLEAR_ONE(frame_T);
     if (*frp == NULL)
-	return;
+	return FAIL;
     (*frp)->fr_layout = fr->fr_layout;
     (*frp)->fr_width = fr->fr_width;
     (*frp)->fr_height = fr->fr_height;
     if (fr->fr_next != NULL)
-	make_snapshot_rec(fr->fr_next, &((*frp)->fr_next));
+    {
+	if (make_snapshot_rec(fr->fr_next, &((*frp)->fr_next)) == FAIL)
+	    return FAIL;
+    }
     if (fr->fr_child != NULL)
-	make_snapshot_rec(fr->fr_child, &((*frp)->fr_child));
+    {
+	if (make_snapshot_rec(fr->fr_child, &((*frp)->fr_child)) == FAIL)
+	    return FAIL;
+    }
     if (fr->fr_layout == FR_LEAF && fr->fr_win == curwin)
 	(*frp)->fr_win = curwin;
+    return OK;
 }
 
 /*
@@ -7737,9 +7904,15 @@ frame_check_width(frame_T *topfrp, int width)
  * Simple int comparison function for use with qsort()
  */
     static int
-int_cmp(const void *a, const void *b)
+int_cmp(const void *pa, const void *pb)
 {
-    return *(const int *)a - *(const int *)b;
+    const int a = *(const int *)pa;
+    const int b = *(const int *)pb;
+    if (a > b)
+	return 1;
+    if (a < b)
+	return -1;
+    return 0;
 }
 
 /*
@@ -7812,3 +7985,9 @@ skip:
     return NULL;  // no error
 }
 #endif
+
+    int
+get_last_winid(void)
+{
+    return last_win_id;
+}