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

[Christian Brabandt]

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

Commit: https://github.com/vim/vim/commit/aee686334c2137f8a94b04de130a3f51d928a7ed
Author: zeertzjq <zeer...@outlook.com>
Date: Mon Aug 3 20:08:04 2026 +0000

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

diff --git a/src/move.c b/src/move.c
index 9b45b0e2b..6e7921cc2 100644
--- 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 9b9eca8cf..d61796a93 100644
--- 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 2fed34c3a..abd19fb95 100644
--- 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,
/**/