fix(folds): combined Folded and Visual highlights (#23752)

Also combine high-priority CursorLine with Folded.

src/nvim/drawline.c

@@ -1049,7 +1049,7 @@ int win_line(win_T *wp, linenr_T lnum, int startrow, int endrow, bool nochange,
 
   static char *at_end_str = "";       // used for p_extra when displaying curwin->w_p_lcs_chars.eol
                                       // at end-of-line
-  bool has_fold = foldinfo.fi_level != 0 && foldinfo.fi_lines > 0;
+  const bool has_fold = foldinfo.fi_level != 0 && foldinfo.fi_lines > 0;
 
   int saved_attr2 = 0;                  // char_attr saved for n_attr
   int n_attr3 = 0;                      // chars with overruling special attr
@@ -1075,6 +1075,7 @@ int win_line(win_T *wp, linenr_T lnum, int startrow, int endrow, bool nochange,
   int vcol_save_attr = 0;               // saved attr for 'cursorcolumn'
   int syntax_attr = 0;                  // attributes desired by syntax
   bool has_syntax = false;              // this buffer has syntax highl.
+  int folded_attr = 0;                  // attributes for folded line
   int save_did_emsg;
   int eol_hl_off = 0;                   // 1 if highlighted char after EOL
   bool draw_color_col = false;          // highlight colorcolumn
@@ -1159,7 +1160,7 @@ int win_line(win_T *wp, linenr_T lnum, int startrow, int endrow, bool nochange,
   wlv.vcol_sbr = -1;
 
   buf_T *buf = wp->w_buffer;
-  bool end_fill = (lnum == buf->b_ml.ml_line_count + 1);
+  const bool end_fill = (lnum == buf->b_ml.ml_line_count + 1);
 
   if (!number_only) {
     // To speed up the loop below, set extra_check when there is linebreak,
@@ -1760,7 +1761,7 @@ int win_line(win_T *wp, linenr_T lnum, int startrow, int endrow, bool nochange,
         && wlv.col == win_col_offset
         && wlv.n_extra == 0
         && wlv.row == startrow + wlv.filler_lines) {
-      wlv.char_attr = win_hl_attr(wp, HLF_FL);
+      wlv.char_attr = folded_attr = win_hl_attr(wp, HLF_FL);
 
       linenr_T lnume = lnum + foldinfo.fi_lines - 1;
       memset(buf_fold, ' ', FOLD_TEXT_LEN);
@@ -1802,7 +1803,7 @@ int win_line(win_T *wp, linenr_T lnum, int startrow, int endrow, bool nochange,
     }
 
     int extmark_attr = 0;
-    if (wlv.draw_state == WL_LINE && !has_fold
+    if (wlv.draw_state == WL_LINE
         && (area_highlighting || has_spell || extra_check)) {
       // handle Visual or match highlighting in this line
       if (wlv.vcol == wlv.fromcol
@@ -1821,6 +1822,7 @@ int win_line(win_T *wp, linenr_T lnum, int startrow, int endrow, bool nochange,
         area_active = false;
       }
 
+      if (!has_fold) {
         if (has_decor && v >= 0) {
           bool selected = (area_active || (area_highlighting && noinvcur
                                            && wlv.vcol == wp->w_virtcol));
@@ -1880,6 +1882,7 @@ int win_line(win_T *wp, linenr_T lnum, int startrow, int endrow, bool nochange,
               : hl_combine_attr(wlv.line_attr, wlv.cul_attr);
           }
         }
+      }
 
       // Decide which of the highlight attributes to use.
       attr_pri = true;
@@ -1908,6 +1911,10 @@ int win_line(win_T *wp, linenr_T lnum, int startrow, int endrow, bool nochange,
           wlv.char_attr = 0;
         }
       }
+
+      if (folded_attr != 0) {
+        wlv.char_attr = hl_combine_attr(folded_attr, wlv.char_attr);
+      }
     }
 
     // Get the next character to put on the screen.

test/functional/ui/decorations_spec.lua

@@ -10,6 +10,7 @@ local expect_events = helpers.expect_events
 local meths = helpers.meths
 local curbufmeths = helpers.curbufmeths
 local command = helpers.command
+local assert_alive = helpers.assert_alive
 
 describe('decorations providers', function()
   local screen
@@ -80,7 +81,7 @@ describe('decorations providers', function()
       local ns2 = api.nvim_create_namespace "ns2"
       api.nvim_set_decoration_provider(ns2, {})
     ]])
-    helpers.assert_alive()
+    assert_alive()
   end)
 
   it('leave a trace', function()
@@ -1092,7 +1093,7 @@ describe('extmark decorations', function()
       {1:~                                                 }|
                                                         |
     ]]}
-    helpers.assert_alive()
+    assert_alive()
   end)
 
   it('conceal #19007', function()
@@ -1258,6 +1259,9 @@ describe('decorations: inline virtual text', function()
       [13] = {reverse = true};
       [14] = {foreground = Screen.colors.SlateBlue, background = Screen.colors.LightMagenta};
       [15] = {bold = true, reverse = true};
+      [16] = {foreground = Screen.colors.Red};
+      [17] = {background = Screen.colors.LightGrey, foreground = Screen.colors.DarkBlue};
+      [18] = {background = Screen.colors.LightGrey, foreground = Screen.colors.Red};
     }
 
     ns = meths.create_namespace 'test'
@@ -1971,6 +1975,37 @@ bbbbbbb]])
       ]],
     })
   end)
+
+  it('does not crash at column 0 when folded in a wide window', function()
+    screen:try_resize(82, 4)
+    command('hi! CursorLine guibg=NONE guifg=Red gui=NONE')
+    command('set cursorline')
+    insert([[
+      aaaaa
+      bbbbb
+      ccccc]])
+    meths.buf_set_extmark(0, ns, 0, 0, { virt_text = {{'foo'}}, virt_text_pos = 'inline' })
+    screen:expect{grid=[[
+      fooaaaaa                                                                          |
+      bbbbb                                                                             |
+      {16:cccc^c                                                                             }|
+                                                                                        |
+    ]]}
+    command('1,2fold')
+    screen:expect{grid=[[
+      {17:+--  2 lines: aaaaa·······························································}|
+      {16:cccc^c                                                                             }|
+      {1:~                                                                                 }|
+                                                                                        |
+    ]]}
+    feed('k')
+    screen:expect{grid=[[
+      {18:^+--  2 lines: aaaaa·······························································}|
+      ccccc                                                                             |
+      {1:~                                                                                 }|
+                                                                                        |
+    ]]}
+  end)
 end)
 
 describe('decorations: virtual lines', function()

test/functional/ui/fold_spec.lua

@@ -42,9 +42,10 @@ describe("folded lines", function()
         [9] = {bold = true, foreground = Screen.colors.Brown},
         [10] = {background = Screen.colors.LightGrey, underline = true},
         [11] = {bold=true},
-        [12] = {background = Screen.colors.Grey90, underline = true},
+        [12] = {foreground = Screen.colors.Red},
-        [13] = {foreground = Screen.colors.DarkBlue, background = Screen.colors.LightGrey, underline = true},
+        [13] = {foreground = Screen.colors.Red, background = Screen.colors.LightGrey},
-        [14] = {background = Screen.colors.LightGray},
+        [14] = {background = Screen.colors.Red},
+        [15] = {foreground = Screen.colors.DarkBlue, background = Screen.colors.Red},
       })
     end)
 
@@ -88,10 +89,9 @@ describe("folded lines", function()
       end
     end)
 
-    it("foldcolumn highlighted with CursorLineFold when 'cursorline' is set", function()
+    local function test_folded_cursorline()
       command("set number cursorline foldcolumn=2")
       command("hi link CursorLineFold Search")
-      command("hi! CursorLine gui=underline guibg=Grey90")
       insert(content1)
       feed("ggzf3jj")
       if multigrid then
@@ -239,6 +239,22 @@ describe("folded lines", function()
                                                        |
         ]])
       end
+    end
+
+    describe("when 'cursorline' is set", function()
+      it('with high-priority CursorLine', function()
+        command("hi! CursorLine guibg=NONE guifg=Red gui=NONE")
+        test_folded_cursorline()
+      end)
+
+      it('with low-priority CursorLine', function()
+        command("hi! CursorLine guibg=NONE guifg=NONE gui=underline")
+        local attrs = screen:get_default_attr_ids()
+        attrs[12] = {underline = true}
+        attrs[13] = {foreground = Screen.colors.DarkBlue, background = Screen.colors.LightGrey, underline = true}
+        screen:set_default_attr_ids(attrs)
+        test_folded_cursorline()
+      end)
     end)
 
     it("work with spell", function()
@@ -2017,7 +2033,8 @@ describe("folded lines", function()
       end
     end)
 
-    it('Folded highlight does not disappear in Visual selection #19691', function()
+    it('Folded and Visual highlights are combined #19691', function()
+      command('hi! Visual guibg=Red')
       insert([[
         " foo
         " {{{1
@@ -2044,9 +2061,9 @@ describe("folded lines", function()
           [3:---------------------------------------------]|
         ## grid 2
           {14:" fo}o                                        |
-          {5:+--  3 lines: "······························}|
+          {15:+-- }{5: 3 lines: "······························}|
           {14:" ba}r                                        |
-          {5:+--  3 lines: "······························}|
+          {15:+-- }{5: 3 lines: "······························}|
           {14:" b}^az                                        |
           {1:~                                            }|
           {1:~                                            }|
@@ -2056,9 +2073,9 @@ describe("folded lines", function()
       else
         screen:expect([[
           {14:" fo}o                                        |
-          {5:+--  3 lines: "······························}|
+          {15:+-- }{5: 3 lines: "······························}|
           {14:" ba}r                                        |
-          {5:+--  3 lines: "······························}|
+          {15:+-- }{5: 3 lines: "······························}|
           {14:" b}^az                                        |
           {1:~                                            }|
           {1:~                                            }|

test/functional/ui/statuscolumn_spec.lua

@@ -196,10 +196,10 @@ describe('statuscolumn', function()
       [2] = {foreground = Screen.colors.DarkBlue, background = Screen.colors.WebGrey},
       [3] = {foreground = Screen.colors.DarkBlue, background = Screen.colors.LightGrey},
       [4] = {bold = true, foreground = Screen.colors.Brown},
-      [5] = {background = Screen.colors.Grey90, underline = true},
+      [5] = {foreground = Screen.colors.Red},
-      [6] = {foreground = Screen.colors.DarkBlue, background = Screen.colors.LightGrey, underline = true},
+      [6] = {foreground = Screen.colors.Red, background = Screen.colors.LightGrey},
     })
-    command('hi! CursorLine gui=underline guibg=Grey90')
+    command('hi! CursorLine guifg=Red guibg=NONE')
     screen:expect([[
       {1: 4│ }aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa|
       {1:  │ }a                                                |