From: zeertzjq <zeertzjq@outlook.com>
Date: Mon, 3 Aug 2026 20:08:04 +0000 (+0000)
Subject: patch 9.2.0904: "zb" scrolls incorrectly with cursor just above fold
X-Git-Tag: v9.2.0904^0
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=aee686334c2137f8a94b04de130a3f51d928a7ed;p=thirdparty%2Fvim.git

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 9b45b0e2bc..6e7921cc2b 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 9b9eca8cfd..d61796a936 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 2fed34c3a1..abd19fb95a 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,
 /**/