vim-patch:9.0.1607: screenpos() returns wrong row with diff filler lines

Problem:    screenpos() returns wrong row with diff filler lines.
Solution:   Only add filler lines when appropriate.  Also don't add the
            'smoothscroll' marker when w_skipcol is zero. (closes vim/vim#12485,
            closes vim/vim#12484)

https://github.com/vim/vim/commit/55daae392157823dc5434e6be1344f4336bfe96f

2 files changed, 21 insertions, 8 deletions

diff --git a/src/nvim/move.c b/src/nvim/move.c
index 57466120e9..4a6c2e1934 100644
--- a/src/nvim/move.c
+++ b/src/nvim/move.c
@@ -1069,21 +1069,20 @@ void textpos2screenpos(win_T *wp, pos_T *pos, int *rowp, int *scolp, int *ccolp,
   bool visible_row = false;
   bool is_folded = false;
 
-  if (pos->lnum >= wp->w_topline && pos->lnum <= wp->w_botline) {
-    linenr_T lnum = pos->lnum;
+  linenr_T lnum = pos->lnum;
+  if (lnum >= wp->w_topline && lnum <= wp->w_botline) {
     is_folded = hasFoldingWin(wp, lnum, &lnum, NULL, true, NULL);
     row = plines_m_win(wp, wp->w_topline, lnum - 1) + 1;
     // Add filler lines above this buffer line.
-    row += win_get_fill(wp, lnum);
+    row += lnum == wp->w_topline ? wp->w_topfill : win_get_fill(wp, lnum);
     visible_row = true;
-  } else if (!local || pos->lnum < wp->w_topline) {
+  } else if (!local || lnum < wp->w_topline) {
     row = 0;
   } else {
     row = wp->w_height_inner;
   }
 
-  bool existing_row = (pos->lnum > 0
-                       && pos->lnum <= wp->w_buffer->b_ml.ml_line_count);
+  bool existing_row = (lnum > 0 && lnum <= wp->w_buffer->b_ml.ml_line_count);
 
   if ((local || visible_row) && existing_row) {
     const colnr_T off = win_col_off(wp);
@@ -1098,7 +1097,7 @@ void textpos2screenpos(win_T *wp, pos_T *pos, int *rowp, int *scolp, int *ccolp,
       col += off;
       int width = wp->w_width_inner - off + win_col_off2(wp);
 
-      if (pos->lnum == wp->w_topline) {
+      if (lnum == wp->w_topline) {
         col -= wp->w_skipcol;
       }
 
diff --git a/test/old/testdir/test_cursor_func.vim b/test/old/testdir/test_cursor_func.vim
index 7c8b691f66..f73bd4f2b9 100644
--- a/test/old/testdir/test_cursor_func.vim
+++ b/test/old/testdir/test_cursor_func.vim
@@ -130,13 +130,14 @@ func Test_screenpos()
   1split
   normal G$
   redraw
+  " w_skipcol should be subtracted
   call assert_equal({'row': winrow + 0,
 	\ 'col': wincol + 20 - 1,
 	\ 'curscol': wincol + 20 - 1,
 	\ 'endcol': wincol + 20 - 1},
 	\ screenpos(win_getid(), line('.'), col('.')))
 
-  " w_skipcol should be subtracted
+  " w_leftcol should be subtracted
   setlocal nowrap
   normal 050zl$
   call assert_equal({'row': winrow + 0,
@@ -203,6 +204,19 @@ func Test_screenpos_diff()
   windo diffthis
   wincmd w
   call assert_equal(#{col: 3, row: 7, endcol: 3, curscol: 3}, screenpos(0, 4, 1))
+  call assert_equal(#{col: 3, row: 8, endcol: 3, curscol: 3}, screenpos(0, 5, 1))
+  exe "normal! 3\<C-E>"
+  call assert_equal(#{col: 3, row: 4, endcol: 3, curscol: 3}, screenpos(0, 4, 1))
+  call assert_equal(#{col: 3, row: 5, endcol: 3, curscol: 3}, screenpos(0, 5, 1))
+  exe "normal! \<C-E>"
+  call assert_equal(#{col: 3, row: 3, endcol: 3, curscol: 3}, screenpos(0, 4, 1))
+  call assert_equal(#{col: 3, row: 4, endcol: 3, curscol: 3}, screenpos(0, 5, 1))
+  exe "normal! \<C-E>"
+  call assert_equal(#{col: 3, row: 2, endcol: 3, curscol: 3}, screenpos(0, 4, 1))
+  call assert_equal(#{col: 3, row: 3, endcol: 3, curscol: 3}, screenpos(0, 5, 1))
+  exe "normal! \<C-E>"
+  call assert_equal(#{col: 3, row: 1, endcol: 3, curscol: 3}, screenpos(0, 4, 1))
+  call assert_equal(#{col: 3, row: 2, endcol: 3, curscol: 3}, screenpos(0, 5, 1))
 
   windo diffoff
   bwipe!