vim-patch:9.0.0701: with 'smoothscroll' cursor position not adjusted in long line

Problem:    With 'smoothscroll' the cursor position s not adjusted in a long
            line.
Solution:   Move the cursor further up or down in the line.

https://github.com/vim/vim/commit/8cf3459878198c5bb4a96f3c63214b2beccce341

Co-authored-by: Bram Moolenaar <Bram@vim.org>

3 files changed, 121 insertions, 1 deletions

diff --git a/src/nvim/move.c b/src/nvim/move.c
index 7c63aa9d7f..144384c294 100644
--- a/src/nvim/move.c
+++ b/src/nvim/move.c
@@ -1208,6 +1208,24 @@ bool scrolldown(long line_count, int byfold)
     foldAdjustCursor();
     coladvance(curwin->w_curswant);
   }
+
+  if (curwin->w_cursor.lnum == curwin->w_topline && do_sms) {
+    // make sure the cursor is in the visible text
+    validate_virtcol();
+    int col = curwin->w_virtcol - curwin->w_skipcol;
+    int row = 0;
+    if (col >= width1) {
+      col -= width1;
+      ++row;
+    }
+    if (col > width2) {
+      row += col / width2;
+      col = col % width2;
+    }
+    if (row >= curwin->w_height) {
+      coladvance(curwin->w_virtcol - (row - curwin->w_height + 1) * width2);
+    }
+  }
   return moved;
 }
 
@@ -1245,7 +1263,7 @@ bool scrollup(long line_count, int byfold)
           // for a closed fold: go to the last line in the fold
           (void)hasFolding(lnum, NULL, &lnum);
         }
-        if (lnum == curwin->w_topline && curwin->w_p_wrap && curwin->w_p_sms) {
+        if (lnum == curwin->w_topline && do_sms) {
           // 'smoothscroll': increase "w_skipcol" until it goes over
           // the end of the line, then advance to the next line.
           int add = curwin->w_skipcol > 0 ? width2 : width1;
@@ -1310,6 +1328,24 @@ bool scrollup(long line_count, int byfold)
     coladvance(curwin->w_curswant);
   }
 
+  if (curwin->w_cursor.lnum == curwin->w_topline && do_sms && curwin->w_skipcol > 0) {
+    // make sure the cursor is in a visible part of the line
+    validate_virtcol();
+    if (curwin->w_virtcol < curwin->w_skipcol + 3) {
+      int width1 = curwin->w_width - curwin_col_off();
+      int width2 = width1 + curwin_col_off2();
+      colnr_T col = curwin->w_virtcol;
+
+      if (col < width1) {
+        col += width1;
+      }
+      while (col < curwin->w_skipcol + 3) {
+        col += width2;
+      }
+      coladvance(col);
+    }
+  }
+
   bool moved = topline != curwin->w_topline
                || botline != curwin->w_botline;
 
diff --git a/test/functional/legacy/scroll_opt_spec.lua b/test/functional/legacy/scroll_opt_spec.lua
index fb4990ff00..5c7c9cd55a 100644
--- a/test/functional/legacy/scroll_opt_spec.lua
+++ b/test/functional/legacy/scroll_opt_spec.lua
@@ -340,4 +340,60 @@ describe('smoothscroll', function()
                                               |
     ]])
   end)
+
+  -- oldtest: Test_smoothscroll_wrap_long_line()
+  it("adjusts the cursor position in a long line", function()
+    screen:try_resize(40, 6)
+    exec([[
+      call setline(1, ['one', 'two', 'Line' .. (' with lots of text'->repeat(30))])
+      set smoothscroll scrolloff=0
+      normal 3G10|zt
+    ]])
+    -- scrolling up, cursor moves screen line down
+    screen:expect([[
+      Line with^ lots of text with lots of text|
+       with lots of text with lots of text wit|
+      h lots of text with lots of text with lo|
+      ts of text with lots of text with lots o|
+      f text with lots of text with lots of te|
+                                              |
+    ]])
+    feed('<C-E>')
+    screen:expect([[
+      <<<th lot^s of text with lots of text wit|
+      h lots of text with lots of text with lo|
+      ts of text with lots of text with lots o|
+      f text with lots of text with lots of te|
+      xt with lots of text with lots of text w|
+                                              |
+    ]])
+    feed('5<C-E>')
+    screen:expect([[
+      <<< lots ^of text with lots of text with |
+      lots of text with lots of text with lots|
+       of text with lots of text with lots of |
+      text with lots of text with lots of text|
+       with lots of text with lots of text wit|
+                                              |
+    ]])
+    -- scrolling down, cursor moves screen line up
+    feed('5<C-Y>')
+    screen:expect([[
+      <<<th lots of text with lots of text wit|
+      h lots of text with lots of text with lo|
+      ts of text with lots of text with lots o|
+      f text with lots of text with lots of te|
+      xt with l^ots of text with lots of text w|
+                                              |
+    ]])
+    feed('<C-Y>')
+    screen:expect([[
+      Line with lots of text with lots of text|
+       with lots of text with lots of text wit|
+      h lots of text with lots of text with lo|
+      ts of text with lots of text with lots o|
+      f text wi^th lots of text with lots of te|
+                                              |
+    ]])
+  end)
 end)
diff --git a/test/old/testdir/test_scroll_opt.vim b/test/old/testdir/test_scroll_opt.vim
index 77e656cf9f..0041fbaa25 100644
--- a/test/old/testdir/test_scroll_opt.vim
+++ b/test/old/testdir/test_scroll_opt.vim
@@ -215,5 +215,33 @@ func Test_smoothscroll_wrap_scrolloff_zero()
   call StopVimInTerminal(buf)
 endfunc
 
+func Test_smoothscroll_wrap_long_line()
+  CheckScreendump
+
+  let lines =<< trim END
+      vim9script
+      setline(1, ['one', 'two', 'Line' .. (' with lots of text'->repeat(30))])
+      set smoothscroll scrolloff=0
+      normal 3G10|zt
+  END
+  call writefile(lines, 'XSmoothWrap', 'D')
+  let buf = RunVimInTerminal('-S XSmoothWrap', #{rows: 6, cols: 40})
+  call VerifyScreenDump(buf, 'Test_smooth_long_1', {})
+
+  " scrolling up, cursor moves screen line down
+  call term_sendkeys(buf, "\<C-E>")
+  call VerifyScreenDump(buf, 'Test_smooth_long_2', {})
+  call term_sendkeys(buf, "5\<C-E>")
+  call VerifyScreenDump(buf, 'Test_smooth_long_3', {})
+
+  " scrolling down, cursor moves screen line up
+  call term_sendkeys(buf, "5\<C-Y>")
+  call VerifyScreenDump(buf, 'Test_smooth_long_4', {})
+  call term_sendkeys(buf, "\<C-Y>")
+  call VerifyScreenDump(buf, 'Test_smooth_long_5', {})
+
+  call StopVimInTerminal(buf)
+endfunc
+
 
 " vim: shiftwidth=2 sts=2 expandtab