patch 9.1.0285: Still problems with cursor position for CTRL-D/U

Problem:  Problems with cursor position when scrolling half a page.
Solution: Rework the cursor logic. (Luuk van Baal)

closes: #14455

Signed-off-by: Luuk van Baal <luukvbaal@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>

src/move.c

@@ -3165,7 +3165,6 @@ static int scroll_with_sms(int dir, long count)
 	// extra for scrolling backward so that consuming skipcol is symmetric.
 	if (labs(curwin->w_topline - prev_topline) > (dir == BACKWARD))
 	    fixdir = dir * -1;
-	validate_cursor();
 	while (curwin->w_skipcol > 0
 	    && curwin->w_topline < curbuf->b_ml.ml_line_count)
 	    scroll_redraw(fixdir == FORWARD, 1);
@@ -3192,6 +3191,7 @@ pagescroll(int dir, long count, int half)
     int		nochange = TRUE;
     int		buflen = curbuf->b_ml.ml_line_count;
     colnr_T	prev_col = curwin->w_cursor.col;
+    colnr_T	prev_curswant = curwin->w_curswant;
     linenr_T	prev_lnum = curwin->w_cursor.lnum;
     oparg_T	oa = { 0 };
     cmdarg_T	ca = { 0 };
@@ -3215,34 +3215,24 @@ pagescroll(int dir, long count, int half)
 		count = n - curwin->w_height;
 	}
 
-	// Scroll the window and determine number of lines to move the cursor.
+	// (Try to) scroll the window unless already at the end of the buffer.
 	if (count > 0)
 	{
-	    validate_cursor();
-	    int prev_wrow = curwin->w_wrow;
 	    nochange = scroll_with_sms(dir, count);
-	    if (!nochange)
+	    curwin->w_cursor.lnum = prev_lnum;
-	    {
+	    curwin->w_cursor.col = prev_col;
-		validate_cursor();
+	    curwin->w_curswant = prev_curswant;
-		curscount = abs(prev_wrow - curwin->w_wrow);
-		dir = prev_wrow > curwin->w_wrow ? FORWARD : BACKWARD;
-	    }
 	}
 
-	int so = get_scrolloff_value();
+	// Move the cursor the same amount of screen lines.
-	// Move the cursor the same amount of screen lines except if
+	if (curwin->w_p_wrap)
-	// 'scrolloff' is set and cursor was at start or end of buffer.
+	    nv_screengo(&oa, dir, curscount);
-	if (so == 0 || (prev_lnum != 1 && prev_lnum != buflen))
+	else if (dir == FORWARD)
-	{
+	    cursor_down_inner(curwin, curscount);
-	    if (curwin->w_p_wrap)
+	else
-		nv_screengo(&oa, dir, curscount);
+	    cursor_up_inner(curwin, curscount);
-	    else if (dir == FORWARD)
-		cursor_down_inner(curwin, curscount);
-	    else
-		cursor_up_inner(curwin, curscount);
-	}
 
-	if (so > 0)
+	if (get_scrolloff_value() > 0)
 	    cursor_correct();
 #ifdef FEAT_FOLDING
 	// Move cursor to first line of closed fold.

src/testdir/test_normal.vim

@@ -4225,4 +4225,16 @@ func Test_single_line_filler_zb()
   bw!
 endfunc
 
+" Test for Ctrl-U not getting stuck at end of buffer with 'scrolloff'.
+func Test_halfpage_scrolloff_eob()
+  set scrolloff=5
+
+  call setline(1, range(1, 100))
+  exe "norm! Gzz\<C-U>zz"
+  call assert_notequal(100, line('.'))
+
+  set scrolloff&
+  bwipe!
+endfunc
+
 " vim: shiftwidth=2 sts=2 expandtab nofoldenable

src/testdir/test_scroll_opt.vim

@@ -1028,10 +1028,10 @@ func Test_smoothscroll_page()
   call assert_equal(415, col('.'))
   exe "norm! \<C-D>"
   call assert_equal(520, winsaveview().skipcol)
-  call assert_equal(535, col('.'))
+  call assert_equal(615, col('.'))
   exe "norm! \<C-D>"
   call assert_equal(520, winsaveview().skipcol)
-  call assert_equal(735, col('.'))
+  call assert_equal(815, col('.'))
   exe "norm! \<C-D>"
   call assert_equal(520, winsaveview().skipcol)
   call assert_equal(895, col('.'))
@@ -1043,10 +1043,10 @@ func Test_smoothscroll_page()
   call assert_equal(495, col('.'))
   exe "norm! \<C-U>"
   call assert_equal(0, winsaveview().skipcol)
-  call assert_equal(375, col('.'))
+  call assert_equal(295, col('.'))
   exe "norm! \<C-U>"
   call assert_equal(0, winsaveview().skipcol)
-  call assert_equal(175, col('.'))
+  call assert_equal(95, col('.'))
   exe "norm! \<C-U>"
   call assert_equal(0, winsaveview().skipcol)
   call assert_equal(15, col('.'))

src/version.c

@@ -704,6 +704,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    285,
 /**/
     284,
 /**/