vim-patch:8.2.2542: highlight of char beyond line end is not correct (#20424)

Problem:    Highlight of char beyond line end is not correct. (Chuan Wei Foo)
Solution:   Fix counting NUL as one cell.  Draw one more character if the EOL
            is part of the match. (closes vim/vim#7883)
https://github.com/vim/vim/commit/41f0895c6e3c7b921e3c102ad42be52b1be48018

Reorder test_search.vim to match Vim.

4 files changed, 104 insertions, 44 deletions

diff --git a/src/nvim/match.c b/src/nvim/match.c
index cd8c65cc02..f41eab889b 100644
--- a/src/nvim/match.c
+++ b/src/nvim/match.c
@@ -738,7 +738,13 @@ int update_search_hl(win_T *wp, linenr_T lnum, colnr_T col, char_u **line, match
 
           if (shl->startcol == shl->endcol) {
             // highlight empty match, try again after it
-            shl->endcol += utfc_ptr2len((char *)(*line) + shl->endcol);
+            char *p = (char *)(*line) + shl->endcol;
+
+            if (*p == NUL) {
+              shl->endcol++;
+            } else {
+              shl->endcol += utfc_ptr2len(p);
+            }
           }
 
           // Loop to check if the match starts at the
@@ -792,12 +798,19 @@ bool get_prevcol_hl_flag(win_T *wp, match_T *search_hl, long curcol)
     prevcol++;
   }
 
-  if (!search_hl->is_addpos && prevcol == search_hl->startcol) {
+  // Highlight a character after the end of the line if the match started
+  // at the end of the line or when the match continues in the next line
+  // (match includes the line break).
+  if (!search_hl->is_addpos && (prevcol == (long)search_hl->startcol
+                                || (prevcol > (long)search_hl->startcol
+                                    && search_hl->endcol == MAXCOL))) {
     return true;
   } else {
     cur = wp->w_match_head;
     while (cur != NULL) {
-      if (!cur->hl.is_addpos && prevcol == cur->hl.startcol) {
+      if (!cur->hl.is_addpos && (prevcol == (long)cur->hl.startcol
+                                 || (prevcol > (long)cur->hl.startcol
+                                     && cur->hl.endcol == MAXCOL))) {
         return true;
       }
       cur = cur->next;
@@ -815,7 +828,6 @@ void get_search_match_hl(win_T *wp, match_T *search_hl, long col, int *char_attr
   bool shl_flag = false;        // flag to indicate whether search_hl
                                 // has been processed or not
 
-  *char_attr = search_hl->attr;
   while (cur != NULL || !shl_flag) {
     if (!shl_flag
         && (cur == NULL || cur->priority > SEARCH_HL_PRIORITY)) {
diff --git a/src/nvim/testdir/test_search.vim b/src/nvim/testdir/test_search.vim
index 3d1bbfb726..0cf55c7d0b 100644
--- a/src/nvim/testdir/test_search.vim
+++ b/src/nvim/testdir/test_search.vim
@@ -956,24 +956,24 @@ func Test_incsearch_search_dump()
   call delete('Xis_search_script')
 endfunc
 
-func Test_hlsearch_block_visual_match()
+func Test_hlsearch_dump()
+  CheckOption hlsearch
   CheckScreendump
 
-  let lines =<< trim END
-    set hlsearch
-    call setline(1, ['aa', 'bbbb', 'cccccc'])
-  END
-  call writefile(lines, 'Xhlsearch_block')
-  let buf = RunVimInTerminal('-S Xhlsearch_block', {'rows': 9, 'cols': 60})
+  call writefile([
+	\ 'set hlsearch cursorline',
+        \ 'call setline(1, ["xxx", "xxx", "xxx"])',
+	\ '/.*',
+	\ '2',
+	\ ], 'Xhlsearch_script')
+  let buf = RunVimInTerminal('-S Xhlsearch_script', {'rows': 6, 'cols': 50})
+  call VerifyScreenDump(buf, 'Test_hlsearch_1', {})
 
-  call term_sendkeys(buf, "G\<C-V>$kk\<Esc>")
-  sleep 100m
-  call term_sendkeys(buf, "/\\%V\<CR>")
-  sleep 100m
-  call VerifyScreenDump(buf, 'Test_hlsearch_block_visual_match', {})
+  call term_sendkeys(buf, "/\\_.*\<CR>")
+  call VerifyScreenDump(buf, 'Test_hlsearch_2', {})
 
   call StopVimInTerminal(buf)
-  call delete('Xhlsearch_block')
+  call delete('Xhlsearch_script')
 endfunc
 
 func Test_hlsearch_and_visual()
@@ -996,6 +996,26 @@ func Test_hlsearch_and_visual()
   call delete('Xhlvisual_script')
 endfunc
 
+func Test_hlsearch_block_visual_match()
+  CheckScreendump
+
+  let lines =<< trim END
+    set hlsearch
+    call setline(1, ['aa', 'bbbb', 'cccccc'])
+  END
+  call writefile(lines, 'Xhlsearch_block')
+  let buf = RunVimInTerminal('-S Xhlsearch_block', {'rows': 9, 'cols': 60})
+
+  call term_sendkeys(buf, "G\<C-V>$kk\<Esc>")
+  sleep 100m
+  call term_sendkeys(buf, "/\\%V\<CR>")
+  sleep 100m
+  call VerifyScreenDump(buf, 'Test_hlsearch_block_visual_match', {})
+
+  call StopVimInTerminal(buf)
+  call delete('Xhlsearch_block')
+endfunc
+
 func Test_incsearch_substitute()
   CheckFunction test_override
   CheckOption incsearch
@@ -1017,6 +1037,21 @@ func Test_incsearch_substitute()
   call Incsearch_cleanup()
 endfunc
 
+func Test_incsearch_substitute_long_line()
+  CheckFunction test_override
+  new
+  call test_override("char_avail", 1)
+  set incsearch
+
+  call repeat('x', 100000)->setline(1)
+  call feedkeys(':s/\%c', 'xt')
+  redraw
+  call feedkeys("\<Esc>", 'xt')
+
+  call Incsearch_cleanup()
+  bwipe!
+endfunc
+
 func Test_hlsearch_cursearch()
   CheckScreendump
 
@@ -1341,21 +1376,6 @@ func Test_subst_word_under_cursor()
   set noincsearch
 endfunc
 
-func Test_incsearch_substitute_long_line()
-  CheckFunction test_override
-  new
-  call test_override("char_avail", 1)
-  set incsearch
-
-  call repeat('x', 100000)->setline(1)
-  call feedkeys(':s/\%c', 'xt')
-  redraw
-  call feedkeys("\<Esc>", 'xt')
-
-  call Incsearch_cleanup()
-  bwipe!
-endfunc
-
 func Test_search_undefined_behaviour()
   CheckFeature terminal
 
diff --git a/test/functional/legacy/search_spec.lua b/test/functional/legacy/search_spec.lua
index 67991f5d48..5a94fca794 100644
--- a/test/functional/legacy/search_spec.lua
+++ b/test/functional/legacy/search_spec.lua
@@ -644,7 +644,35 @@ end)
 
 describe('Search highlight', function()
   before_each(clear)
-  it('Search highlight is combined with Visual highlight vim-patch:8.2.2797', function()
+
+  -- oldtest: Test_hlsearch_dump()
+  it('beyond line end vim-patch:8.2.2542', function()
+    local screen = Screen.new(50, 6)
+    screen:set_default_attr_ids({
+      [1] = {bold = true, foreground = Screen.colors.Blue},  -- NonText
+      [2] = {background = Screen.colors.Yellow},  -- Search
+      [3] = {background = Screen.colors.Grey90},  -- CursorLine
+    })
+    screen:attach()
+    exec([[
+      set hlsearch noincsearch cursorline
+      call setline(1, ["xxx", "xxx", "xxx"])
+      /.*
+      2
+    ]])
+    feed([[/\_.*<CR>]])
+    screen:expect([[
+      {2:xxx }                                              |
+      {2:xxx }                                              |
+      {2:^xxx }{3:                                              }|
+      {1:~                                                 }|
+      {1:~                                                 }|
+      /\_.*                                             |
+    ]])
+  end)
+
+  -- oldtest: Test_hlsearch_and_visual()
+  it('is combined with Visual highlight vim-patch:8.2.2797', function()
     local screen = Screen.new(40, 6)
     screen:set_default_attr_ids({
       [1] = {bold = true, foreground = Screen.colors.Blue},  -- NonText
diff --git a/test/functional/ui/searchhl_spec.lua b/test/functional/ui/searchhl_spec.lua
index c5c88323a2..18bbb56a61 100644
--- a/test/functional/ui/searchhl_spec.lua
+++ b/test/functional/ui/searchhl_spec.lua
@@ -221,10 +221,10 @@ describe('search highlighting', function()
       feed('gg/foo\\nbar<CR>')
       screen:expect([[
         one                                     |
-        {2:^foo}                                     |
+        {2:^foo }                                    |
         {2:bar}                                     |
         baz                                     |
-        {1:foo}                                     |
+        {1:foo }                                    |
         {1:bar}                                     |
         /foo\nbar                               |
       ]])
@@ -232,20 +232,20 @@ describe('search highlighting', function()
       feed('gg/efg\\nhij<CR>')
       screen:expect([[
         ---                                     |
-        abcd{2:^efg}                                 |
+        abcd{2:^efg }                                |
         {2:hij}kl                                   |
         ---                                     |
-        abcd{1:efg}                                 |
+        abcd{1:efg }                                |
         {1:hij}kl                                   |
         /efg\nhij                               |
       ]])
       feed('n')
       screen:expect([[
         ---                                     |
-        abcd{1:efg}                                 |
+        abcd{1:efg }                                |
         {1:hij}kl                                   |
         ---                                     |
-        abcd{2:^efg}                                 |
+        abcd{2:^efg }                                |
         {2:hij}kl                                   |
         /efg\nhij                               |
       ]])
@@ -548,9 +548,9 @@ describe('search highlighting', function()
     feed('/line\\na<cr>')
     screen:expect([[
                                               |
-      a  repeated {2:^line}                        |
-      {2:a}  repeated {2:line}                        |
-      {2:a}  repeated {2:line}                        |
+      a  repeated {2:^line }                       |
+      {2:a}  repeated {2:line }                       |
+      {2:a}  repeated {2:line }                       |
       {2:a}  repeated line                        |
       {1:~                                       }|
       {4:search hit BOTTOM, continuing at TOP}    |
@@ -560,9 +560,9 @@ describe('search highlighting', function()
     feed('4Grb')
     screen:expect([[
                                               |
-      a  repeated {2:line}                        |
+      a  repeated {2:line }                       |
       {2:a}  repeated line                        |
-      ^b  repeated {2:line}                        |
+      ^b  repeated {2:line }                       |
       {2:a}  repeated line                        |
       {1:~                                       }|
       {4:search hit BOTTOM, continuing at TOP}    |