vim-patch:9.0.1542: line not fully displayed if it doesn't fit in the screen

Problem:    Line not fully displayed if it doesn't fit in the screen.
Solution:   Do not reset s_skipcol if not needed. (Luuk van Baal,
            closes vim/vim#12376)

6c018680be

src/nvim/move.c

@@ -2090,10 +2090,9 @@ void scroll_cursor_halfway(bool atend, bool prefer_above)
   colnr_T skipcol = 0;
 
   int want_height;
-  bool smooth_scroll = false;
+  bool do_sms = curwin->w_p_wrap && curwin->w_p_sms;
-  if (curwin->w_p_sms && curwin->w_p_wrap) {
+  if (do_sms) {
     // 'smoothscroll' and 'wrap' are set
-    smooth_scroll = true;
     if (atend) {
       want_height = (curwin->w_height_inner - used) / 2;
       used = 0;
@@ -2106,7 +2105,7 @@ void scroll_cursor_halfway(bool atend, bool prefer_above)
   while (topline > 1) {
     // If using smoothscroll, we can precisely scroll to the
     // exact point where the cursor is halfway down the screen.
-    if (smooth_scroll) {
+    if (do_sms) {
       topline_back_winheight(curwin, &loff, false);
       if (loff.height == MAXCOL) {
         break;
@@ -2190,7 +2189,7 @@ void scroll_cursor_halfway(bool atend, bool prefer_above)
     if (skipcol != 0) {
       curwin->w_skipcol = skipcol;
       redraw_later(curwin, UPD_NOT_VALID);
-    } else {
+    } else if (do_sms) {
       reset_skipcol(curwin);
     }
   }

test/functional/legacy/display_spec.lua

@@ -196,7 +196,7 @@ describe('display', function()
   end)
 
   -- oldtest: Test_display_long_lastline()
-  it('display "lastline" shows correct text when end of wrapped line is deleted', function()
+  it('"lastline" shows correct text when end of wrapped line is deleted', function()
     local screen = Screen.new(35, 14)
     screen:attach()
     exec([[
@@ -241,4 +241,24 @@ describe('display', function()
                                          |
     ]])
   end)
+
+  -- oldtest: Test_display_cursor_long_line()
+  it("correctly shows line that doesn't fit in the window", function()
+    local screen = Screen.new(75, 8)
+    screen:attach()
+    exec([[
+      call setline(1, ['a', 'bbbbb '->repeat(100), 'c'])
+      norm $j
+    ]])
+    screen:expect([[
+      <<<bbbbb bbbbb bbbbb bbbbb bbbbb bbbbb bbbbb bbbbb bbbbb bbbbb bbbbb bbbbb |
+      bbbbb bbbbb bbbbb bbbbb bbbbb bbbbb bbbbb bbbbb bbbbb bbbbb bbbbb bbbbb bbb|
+      bb bbbbb bbbbb bbbbb bbbbb bbbbb bbbbb bbbbb bbbbb bbbbb bbbbb bbbbb bbbbb |
+      bbbbb bbbbb bbbbb bbbbb bbbbb bbbbb bbbbb bbbbb bbbbb bbbbb bbbbb bbbbb bbb|
+      bb bbbbb bbbbb bbbbb bbbbb bbbbb bbbbb bbbbb bbbbb bbbbb bbbbb bbbbb bbbbb |
+      bbbbb bbbbb bbbbb bbbbb bbbbb bbbbb bbbbb bbbbb bbbbb bbbbb bbbbb bbbbb bbb|
+      bb bbbbb bbbbb bbbbb bbbbb bbbbb bbbbb bbbbb bbbbb bbbbb bbbbb bbbbb bbbbb^ |
+                                                                                 |
+    ]])
+  end)
 end)

test/old/testdir/test_display.vim

@@ -500,4 +500,22 @@ func Test_display_long_lastline()
   call StopVimInTerminal(buf)
 endfunc
 
+" Moving the cursor to a line that doesn't fit in the window should show
+" correctly.
+func Test_display_cursor_long_line()
+  CheckScreendump
+
+  let lines =<< trim END
+    call setline(1, ['a', 'bbbbb '->repeat(100), 'c'])
+    norm $j
+  END
+
+  call writefile(lines, 'XdispCursorLongline', 'D')
+  let buf = RunVimInTerminal('-S XdispCursorLongline', #{rows: 8})
+
+  call VerifyScreenDump(buf, 'Test_display_cursor_long_line', {})
+
+  call StopVimInTerminal(buf)
+endfunc
+
 " vim: shiftwidth=2 sts=2 expandtab