# HG changeset patch
# User Bram Moolenaar <Bram@vim.org>
# Date 1597861804 -7200
# Node ID 7fb29e719d79a1f91ac00f81e22336955a1c8c13
# Parent  43877f9603c1b3a45f9c7b7dfce449b6abd1ea9f
patch 8.2.1488: text does not scroll when inserting above first line

Commit: https://github.com/vim/vim/commit/9dc1917f42b23277e143fc58bbe27482b0b76bad
Author: Bram Moolenaar <Bram@vim.org>
Date:   Wed Aug 19 20:19:48 2020 +0200

    patch 8.2.1488: text does not scroll when inserting above first line

    Problem:    Text does not scroll when inserting above first line.
    Solution:   Adjust off-by-one error. (Ken Takata, closes https://github.com/vim/vim/issues/6739)

diff --git a/src/drawscreen.c b/src/drawscreen.c
--- a/src/drawscreen.c
+++ b/src/drawscreen.c
@@ -1662,7 +1662,7 @@ win_update(win_T *wp)
 	if (mod_top != 0
 		&& wp->w_topline == mod_top
 		&& (!wp->w_lines[0].wl_valid
-		    || wp->w_topline == wp->w_lines[0].wl_lnum))
+		    || wp->w_topline <= wp->w_lines[0].wl_lnum))
 	{
 	    // w_topline is the first changed line and window is not scrolled,
 	    // the scrolling from changed lines will be done further down.
diff --git a/src/testdir/dumps/Test_display_scroll_at_topline.dump b/src/testdir/dumps/Test_display_scroll_at_topline.dump
new file mode 100644
--- /dev/null
+++ b/src/testdir/dumps/Test_display_scroll_at_topline.dump
@@ -0,0 +1,4 @@
+> +0&#ffffff0@19
+|a@19
+@1| @18
+|~+0#4040ff13&| @18
diff --git a/src/testdir/test_display.vim b/src/testdir/test_display.vim
--- a/src/testdir/test_display.vim
+++ b/src/testdir/test_display.vim
@@ -245,4 +245,16 @@ func Test_visual_block_scroll()
   call delete(filename)
 endfunc
 
+func Test_display_scroll_at_topline()
+  CheckScreendump
+
+  let buf = RunVimInTerminal('', #{cols: 20})
+  call term_sendkeys(buf, ":call setline(1, repeat('a', 21))\<CR>")
+  call term_wait(buf)
+  call term_sendkeys(buf, "O\<Esc>")
+  call VerifyScreenDump(buf, 'Test_display_scroll_at_topline', #{rows: 4})
+
+  call StopVimInTerminal(buf)
+endfunc
+
 " vim: shiftwidth=2 sts=2 expandtab
diff --git a/src/version.c b/src/version.c
--- a/src/version.c
+++ b/src/version.c
@@ -755,6 +755,8 @@ static char *(features[]) =
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1488,
+/**/
     1487,
 /**/
     1486,