From 8e4a4629cab3377ba6fd5e291cf5f17fb4ff8a5c Mon Sep 17 00:00:00 2001
From: Luuk van Baal <luukvbaal@gmail.com>
Date: Wed, 26 Apr 2023 16:54:23 +0200
Subject: vim-patch:9.0.0671: negative topline using CTRL-Y with 'smoothscroll'
 and 'diff'

Problem:    Negative topline using CTRL-Y with 'smoothscroll' and 'diff'.
            (Ernie Rael)
Solution:   Only use 'smoothscroll' when 'wrap' is set.

https://github.com/vim/vim/commit/1a58e1d97cfc72e501cbf63ad75f46f1bb4c8da2

Co-authored-by: Bram Moolenaar <Bram@vim.org>
---
 test/functional/legacy/scroll_opt_spec.lua | 29 +++++++++++++++++++++++++++++
 test/old/testdir/test_scroll_opt.vim       | 26 ++++++++++++++++++++++++++
 2 files changed, 55 insertions(+)

(limited to 'test')

diff --git a/test/functional/legacy/scroll_opt_spec.lua b/test/functional/legacy/scroll_opt_spec.lua
index 8d2eade1a8..90417d93f3 100644
--- a/test/functional/legacy/scroll_opt_spec.lua
+++ b/test/functional/legacy/scroll_opt_spec.lua
@@ -272,4 +272,33 @@ describe('smoothscroll', function()
                                               |
     ]])
   end)
+
+  -- oldtest: Test_smoothscroll_diff_mode()
+  it("works with diff mode", function()
+    screen:try_resize(40, 8)
+    exec([[
+      let text = 'just some text here'
+      call setline(1, text)
+      set smoothscroll
+      diffthis
+      new
+      call setline(1, text)
+      set smoothscroll
+      diffthis
+    ]])
+    screen:expect([[
+      - ^just some text here                   |
+      ~                                       |
+      ~                                       |
+      [No Name] [+]                           |
+      - just some text here                   |
+      ~                                       |
+      [No Name] [+]                           |
+                                              |
+    ]])
+    feed('<C-Y>')
+    screen:expect_unchanged()
+    feed('<C-E>')
+    screen:expect_unchanged()
+  end)
 end)
diff --git a/test/old/testdir/test_scroll_opt.vim b/test/old/testdir/test_scroll_opt.vim
index f574286b09..53768de6fa 100644
--- a/test/old/testdir/test_scroll_opt.vim
+++ b/test/old/testdir/test_scroll_opt.vim
@@ -158,6 +158,32 @@ func Test_smoothscroll_number()
   call StopVimInTerminal(buf)
 endfunc
 
+func Test_smoothscroll_diff_mode()
+  CheckScreendump
+
+  let lines =<< trim END
+      vim9script
+      var text = 'just some text here'
+      setline(1, text)
+      set smoothscroll
+      diffthis
+      new
+      setline(1, text)
+      set smoothscroll
+      diffthis
+  END
+  call writefile(lines, 'XSmoothDiff', 'D')
+  let buf = RunVimInTerminal('-S XSmoothDiff', #{rows: 8})
+
+  call VerifyScreenDump(buf, 'Test_smooth_diff_1', {})
+  call term_sendkeys(buf, "\<C-Y>")
+  call VerifyScreenDump(buf, 'Test_smooth_diff_1', {})
+  call term_sendkeys(buf, "\<C-E>")
+  call VerifyScreenDump(buf, 'Test_smooth_diff_1', {})
+
+  call StopVimInTerminal(buf)
+endfunc
+
 
 
 " vim: shiftwidth=2 sts=2 expandtab
-- 
cgit