test(extmarks): add test for virt_text_hide with 'smoothscroll' (#23791)

runtime/doc/api.txt

@@ -2614,8 +2614,9 @@ nvim_buf_set_extmark({buffer}, {ns_id}, {line}, {col}, {*opts})
                   • virt_text_win_col : position the virtual text at a fixed
                     window column (starting from the first text column)
                   • virt_text_hide : hide the virtual text when the background
-                    text is selected or hidden due to horizontal scroll
+                    text is selected or hidden because of scrolling with
-                    'nowrap'
+                    'nowrap' or 'smoothscroll'. Currently only affects
+                    "overlay" virt_text.
                   • hl_mode : control how highlights are combined with the
                     highlights of the text. Currently only affects virt_text
                     highlights, but might affect `hl_group` in later versions.

src/nvim/api/extmark.c

@@ -483,8 +483,9 @@ Array nvim_buf_get_extmarks(Buffer buffer, Integer ns_id, Object start, Object e
 ///                                     window column (starting from the first
 ///                                     text column)
 ///               - virt_text_hide : hide the virtual text when the background
-///                                  text is selected or hidden due to
+///                                  text is selected or hidden because of
-///                                  horizontal scroll 'nowrap'
+///                                  scrolling with 'nowrap' or 'smoothscroll'.
+///                                  Currently only affects "overlay" virt_text.
 ///               - hl_mode : control how highlights are combined with the
 ///                           highlights of the text. Currently only affects
 ///                           virt_text highlights, but might affect `hl_group`

src/nvim/drawline.c

@@ -1727,7 +1727,7 @@ int win_line(win_T *wp, linenr_T lnum, int startrow, int endrow, int mod_top, bo
         sign_idx = 0;
         wlv.draw_state = WL_LINE;
         if (has_decor && wlv.row == startrow + wlv.filler_lines) {
-          // hide virt_text on text hidden by 'nowrap'
+          // hide virt_text on text hidden by 'nowrap' or 'smoothscroll'
           decor_redraw_col(wp, (colnr_T)(ptr - line), wlv.off, true, &decor_state);
         }
         win_line_continue(&wlv);  // use wlv.saved_ values

test/functional/ui/decorations_spec.lua

@@ -827,24 +827,53 @@ describe('extmark decorations', function()
       end  -- ?古古古古?古古                                                            |
                                                                                         |
     ]]}
+  end)
 
-    screen:try_resize(50, 2)
+  it('virt_text_hide hides overlay virtual text when extmark is off-screen', function()
+    screen:try_resize(50, 3)
     command('set nowrap')
-    meths.buf_set_lines(0, 12, 12, true, {'-- ' .. ('…'):rep(57)})
+    meths.buf_set_lines(0, 0, -1, true, {'-- ' .. ('…'):rep(57)})
-    feed('G')
+    meths.buf_set_extmark(0, ns, 0, 123, { virt_text={{'!!!!!', 'ErrorMsg'}}, virt_text_pos='overlay', virt_text_hide=true})
-    meths.buf_set_extmark(0, ns, 12, 123, { virt_text={{'!!!!!', 'ErrorMsg'}}, virt_text_pos='overlay', virt_text_hide=true})
     screen:expect{grid=[[
       ^-- …………………………………………………………………………………………………………{4:!!!!!}……|
+      {1:~                                                 }|
                                                         |
     ]]}
     feed('40zl')
     screen:expect{grid=[[
       ^………{4:!!!!!}………………………………                              |
+      {1:~                                                 }|
                                                         |
     ]]}
     feed('10zl')
     screen:expect{grid=[[
       ^…………………………                                        |
+      {1:~                                                 }|
+                                                        |
+    ]]}
+
+    command('set wrap smoothscroll')
+    screen:expect{grid=[[
+      -- …………………………………………………………………………………………………………{4:!!!!!}……|
+      ^…………………………                                        |
+                                                        |
+    ]]}
+    feed('<C-E>')
+    screen:expect{grid=[[
+      {1:<<<}………………^…                                        |
+      {1:~                                                 }|
+                                                        |
+    ]]}
+    screen:try_resize(40, 3)
+    screen:expect{grid=[[
+      {1:<<<}{4:!!!!!}……………………………^…                    |
+      {1:~                                       }|
+                                              |
+    ]]}
+    feed('<C-Y>')
+    screen:expect{grid=[[
+      -- …………………………………………………………………………………………………|
+      ………{4:!!!!!}……………………………^…                    |
                                               |
     ]]}
   end)