vim-patch:9.0.0757: line number not visisble with 'smoothscroll', 'nu' and 'rnu'

Problem:    Line number not visisble with 'smoothscroll', 'nu' and 'rnu'.
Solution:   Put the ">>>" after the line number instead of on top.

https://github.com/vim/vim/commit/eb4de629315f2682d8b314462d02422ec98d751a

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

4 files changed, 51 insertions, 4 deletions

diff --git a/src/nvim/drawline.c b/src/nvim/drawline.c
index 0d701f07bb..ef9912e503 100644
--- a/src/nvim/drawline.c
+++ b/src/nvim/drawline.c
@@ -609,7 +609,7 @@ static void handle_lnum_col(win_T *wp, winlinevars_T *wlv, int num_signs, int si
     } else {
       // Draw the line number (empty space after wrapping).
       if (wlv->row == wlv->startrow + wlv->filler_lines
-          && (wp->w_skipcol == 0 || wlv->row > wp->w_winrow)) {
+          && (wp->w_skipcol == 0 || wlv->row > wp->w_winrow || (wp->w_p_nu && wp->w_p_rnu))) {
         get_line_number_str(wp, wlv->lnum, wlv->extra, sizeof(wlv->extra));
         if (wp->w_skipcol > 0 && wlv->startrow == 0) {
           for (wlv->p_extra = wlv->extra; *wlv->p_extra == ' '; wlv->p_extra++) {
diff --git a/src/nvim/grid.c b/src/nvim/grid.c
index 0ceaeaa8b2..8431c078b9 100644
--- a/src/nvim/grid.c
+++ b/src/nvim/grid.c
@@ -533,9 +533,21 @@ void grid_put_linebuf(ScreenGrid *grid, int row, int coloff, int endcol, int cle
   if (topline && wp->w_skipcol > 0 && *get_showbreak_value(wp) == NUL) {
     // Take care of putting "<<<" on the first line for 'smoothscroll'
     // when 'showbreak' is not set.
-    for (int i = 0; i < 3; i++) {
-      schar_from_ascii(linebuf_char[i], '<');
-      linebuf_attr[i] = HL_ATTR(HLF_AT);
+    int off = 0;
+    int skip = 0;
+    if (wp->w_p_nu && wp->w_p_rnu) {
+      // do not overwrite the line number, change "123 text" to
+      // "123>>>xt".
+      while (skip < wp->w_width && ascii_isdigit(*linebuf_char[off])) {
+        off++;
+        skip++;
+      }
+    }
+
+    for (int i = 0; i < 3 && i + skip < wp->w_width; i++) {
+      schar_from_ascii(linebuf_char[off], '<');
+      linebuf_attr[off] = HL_ATTR(HLF_AT);
+      off++;
     }
   }
 
diff --git a/test/functional/legacy/scroll_opt_spec.lua b/test/functional/legacy/scroll_opt_spec.lua
index a5660ae4d2..5e54470bd4 100644
--- a/test/functional/legacy/scroll_opt_spec.lua
+++ b/test/functional/legacy/scroll_opt_spec.lua
@@ -181,6 +181,12 @@ describe('smoothscroll', function()
       set smoothscroll scrolloff=5
       set number cpo+=n
       :3
+      func g:DoRel()
+        set number relativenumber scrolloff=0
+        :%del
+        call setline(1, [ 'one', 'very long text '->repeat(12), 'three', ])
+        exe "normal 2Gzt\<C-E>"
+      endfunc
     ]])
     screen:expect([[
         1 one word word word word word word wo|
@@ -271,6 +277,21 @@ describe('smoothscroll', function()
       ~                                       |
                                               |
     ]])
+    exec('call DoRel()')
+    screen:expect([[
+      2<<<ong text very long text very lon^g te|
+          xt very long text very long text ver|
+          y long text very long text very long|
+           text very long text very long text |
+        1 three                               |
+      ~                                       |
+      ~                                       |
+      ~                                       |
+      ~                                       |
+      ~                                       |
+      ~                                       |
+      --No lines in buffer--                  |
+    ]])
   end)
 
   -- oldtest: Test_smoothscroll_diff_mode()
diff --git a/test/old/testdir/test_scroll_opt.vim b/test/old/testdir/test_scroll_opt.vim
index a8e0a1109a..c394c6adf8 100644
--- a/test/old/testdir/test_scroll_opt.vim
+++ b/test/old/testdir/test_scroll_opt.vim
@@ -138,6 +138,17 @@ func Test_smoothscroll_number()
       set smoothscroll
       set number cpo+=n
       :3
+
+      def g:DoRel()
+        set number relativenumber scrolloff=0
+        :%del
+        setline(1, [
+          'one',
+          'very long text '->repeat(12),
+          'three',
+        ])
+        exe "normal 2Gzt\<C-E>"
+      enddef
   END
   call writefile(lines, 'XSmoothNumber', 'D')
   let buf = RunVimInTerminal('-S XSmoothNumber', #{rows: 12, cols: 40})
@@ -155,6 +166,9 @@ func Test_smoothscroll_number()
   call term_sendkeys(buf, "\<C-Y>")
   call VerifyScreenDump(buf, 'Test_smooth_number_6', {})
 
+  call term_sendkeys(buf, ":call DoRel()\<CR>")
+  call VerifyScreenDump(buf, 'Test_smooth_number_7', {})
+
   call StopVimInTerminal(buf)
 endfunc