patch 9.2.0904: "zb" scrolls incorrectly with cursor just above fold

Problem:  "zb" scrolls incorrectly with cursor just above fold.
Solution: Handle boff.lnum being set to the last line of a fold
          (zeertzjq).

With the cursor just above fold, botline_forw() moves boff.lnum to the
last line of the fold, but curwin->w_botline is at the first line of the
fold, so the boff.lnum == curwin->w_botline condition never holds.

Instead, check that boff.lnum has just moved to or past w_botline by
comparing its previous value with w_botline.

Also make a similar change to the loff.lnum check above for symmetry.
That one doesn't change behavior, as topline_back() sets loff.lnum to
the first line of a fold.

related: neovim/neovim#41122
closes:  #20923

Signed-off-by: zeertzjq <zeertzjq@outlook.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>

diff --git a/src/move.c b/src/move.c
index 9b45b0e2bc9de62dfc14fefb586ffc3cfbbc3105..6e7921cc2b80eabbb064e2ef8e584f3d6be69eca 100644 (file)
--- a/src/move.c
+++ b/src/move.c
@@ -2790,6 +2790,7 @@ scroll_cursor_bot(int min_scroll, int set_topbot)
                )
            break;
 
+       linenr_T loff_lnum_before = loff.lnum;
        // Add one line above
        topline_back(&loff);
        if (loff.height == MAXCOL)
@@ -2808,15 +2809,13 @@ scroll_cursor_bot(int min_scroll, int set_topbot)
            // Count screen lines that are below the window.
            scrolled += loff.height;
            if (loff.lnum == curwin->w_botline
-#ifdef FEAT_DIFF
-                           && loff.fill == 0
-#endif
-                   )
+                   && loff_lnum_before > curwin->w_botline)
                scrolled -= curwin->w_empty_rows;
        }
 
        if (boff.lnum < curbuf->b_ml.ml_line_count)
        {
+           linenr_T boff_lnum_before = boff.lnum;
            // Add one line below
            botline_forw(&boff);
            used += boff.height;
@@ -2835,11 +2834,8 @@ scroll_cursor_bot(int min_scroll, int set_topbot)
                {
                    // Count screen lines that are below the window.
                    scrolled += boff.height;
-                   if (boff.lnum == curwin->w_botline
-#ifdef FEAT_DIFF
-                           && boff.fill == 0
-#endif
-                           )
+                   if (boff.lnum >= curwin->w_botline
+                           && boff_lnum_before < curwin->w_botline)
                        scrolled -= curwin->w_empty_rows;
                }
            }

diff --git a/src/testdir/test_normal.vim b/src/testdir/test_normal.vim
index 9b9eca8cfd8a42d5df91981774ca8d28d3092dc6..d61796a93627fd2070c0673252b127ea73b5c7f2 100644 (file)
--- a/src/testdir/test_normal.vim
+++ b/src/testdir/test_normal.vim
@@ -4397,16 +4397,21 @@ func Test_single_line_filler_zb()
 endfunc
 
 " Test for zb with fewer buffer lines than window height, non-zero 'scrolloff'
-" and cursor on fold.
-func Test_zb_with_cursor_on_fold()
+" and cursor on or just above a fold.
+func Test_zb_with_cursor_on_or_just_above_fold()
   15new
   call setline(1, range(1, 5) + ['', 'foo{{{', 'bar}}}', '', 'baz'])
   setlocal foldmethod=marker scrolloff=1
   call assert_equal(8, foldclosedend(7))
+
   call cursor(7, 1)
   normal! zb
   call assert_equal(1, line('w0'))
 
+  call cursor(6, 1)
+  normal! zb
+  call assert_equal(1, line('w0'))
+
   bwipe!
 endfunc
 

diff --git a/src/version.c b/src/version.c
index 2fed34c3a1d50382172fd29aa98c1d65d8bc342a..abd19fb95acf68c560e12a6e471709aabcb963af 100644 (file)
--- a/src/version.c
+++ b/src/version.c
@@ -763,6 +763,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    904,
 /**/
     903,
 /**/