vim-patch:9.0.0664: bad redrawing with spell checking, using "C" and "$" in 'cpo'

Problem:    Bad redrawing with spell checking, using "C" and "$" in 'cpo'.
Solution:   Do not redraw the next line when "$" is in 'cpo'. (closes vim/vim#11285)

https://github.com/vim/vim/commit/f3ef026c9897f1d2e3fba47166a4771d507dae91

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

4 files changed, 67 insertions, 22 deletions

diff --git a/src/nvim/change.c b/src/nvim/change.c
index ebbb0d4db6..9e1767c2f3 100644
--- a/src/nvim/change.c
+++ b/src/nvim/change.c
@@ -397,7 +397,10 @@ void changed_bytes(linenr_T lnum, colnr_T col)
   // When text has been changed at the end of the line, possibly the start of
   // the next line may have SpellCap that should be removed or it needs to be
   // displayed.  Schedule the next line for redrawing just in case.
-  if (spell_check_window(curwin) && lnum < curbuf->b_ml.ml_line_count) {
+  // Don't do this when displaying '$' at the end of changed text.
+  if (spell_check_window(curwin)
+      && lnum < curbuf->b_ml.ml_line_count
+      && vim_strchr(p_cpo, CPO_DOLLAR) == NULL) {
     redrawWinline(curwin, lnum + 1);
   }
   // notify any channels that are watching
diff --git a/src/nvim/edit.c b/src/nvim/edit.c
index c0f094453d..d6d5ff8ac7 100644
--- a/src/nvim/edit.c
+++ b/src/nvim/edit.c
@@ -1527,8 +1527,8 @@ void edit_unputchar(void)
   }
 }
 
-// Called when p_dollar is set: display a '$' at the end of the changed text
-// Only works when cursor is in the line that changes.
+/// Called when "$" is in 'cpoptions': display a '$' at the end of the changed
+/// text.  Only works when cursor is in the line that changes.
 void display_dollar(colnr_T col_arg)
 {
   colnr_T col = col_arg < 0 ? 0 : col_arg;
diff --git a/test/functional/ui/spell_spec.lua b/test/functional/ui/spell_spec.lua
index 800043b169..7f11b06f78 100644
--- a/test/functional/ui/spell_spec.lua
+++ b/test/functional/ui/spell_spec.lua
@@ -27,6 +27,7 @@ describe("'spell'", function()
       [6] = {foreground = Screen.colors.Red},
       [7] = {foreground = Screen.colors.Blue},
       [8] = {foreground = Screen.colors.Blue, special = Screen.colors.Red, undercurl = true},
+      [9] = {bold = true},
     })
   end)
 
@@ -141,6 +142,40 @@ describe("'spell'", function()
     ]])
   end)
 
+  -- oldtest: Test_spell_compatible()
+  it([[redraws properly when using "C" and "$" is in 'cpo']], function()
+    exec([=[
+      call setline(1, [
+        \ "test "->repeat(20),
+        \ "",
+        \ "end",
+      \ ])
+      set spell cpo+=$
+    ]=])
+    feed('51|C')
+    screen:expect([[
+      {2:test} test test test test test test test test test ^test test test test test test |
+      test test test test$                                                            |
+                                                                                      |
+      {2:end}                                                                             |
+      {0:~                                                                               }|
+      {0:~                                                                               }|
+      {0:~                                                                               }|
+      {9:-- INSERT --}                                                                    |
+    ]])
+    feed('x')
+    screen:expect([[
+      {2:test} test test test test test test test test test x^est test test test test test |
+      test test test test$                                                            |
+                                                                                      |
+      {2:end}                                                                             |
+      {0:~                                                                               }|
+      {0:~                                                                               }|
+      {0:~                                                                               }|
+      {9:-- INSERT --}                                                                    |
+    ]])
+  end)
+
   it('extmarks, "noplainbuffer" and syntax #20385 #23398', function()
     exec('set filetype=c')
     exec('syntax on')
diff --git a/test/old/testdir/test_spell.vim b/test/old/testdir/test_spell.vim
index c959e199d9..14d6ce30c4 100644
--- a/test/old/testdir/test_spell.vim
+++ b/test/old/testdir/test_spell.vim
@@ -972,28 +972,12 @@ func Test_spell_screendump()
              \ ])
        set spell spelllang=en_nz
   END
-  call writefile(lines, 'XtestSpell')
-  let buf = RunVimInTerminal('-S XtestSpell', {'rows': 8})
-  call VerifyScreenDump(buf, 'Test_spell_1', {})
-
-  let lines =<< trim END
-       call setline(1, [
-             \ "This is some text without any spell errors.  Everything",
-             \ "should just be black, nothing wrong here.",
-             \ "",
-             \ "This line has a sepll error. and missing caps.",
-             \ "And and this is the the duplication.",
-             \ "with missing caps here.",
-             \ ])
-       set spell spelllang=en_nz
-  END
-  call writefile(lines, 'XtestSpell')
+  call writefile(lines, 'XtestSpell', 'D')
   let buf = RunVimInTerminal('-S XtestSpell', {'rows': 8})
   call VerifyScreenDump(buf, 'Test_spell_1', {})
 
   " clean up
   call StopVimInTerminal(buf)
-  call delete('XtestSpell')
 endfunc
 
 func Test_spell_screendump_spellcap()
@@ -1010,7 +994,7 @@ func Test_spell_screendump_spellcap()
              \ ])
        set spell spelllang=en
   END
-  call writefile(lines, 'XtestSpellCap')
+  call writefile(lines, 'XtestSpellCap', 'D')
   let buf = RunVimInTerminal('-S XtestSpellCap', {'rows': 8})
   call VerifyScreenDump(buf, 'Test_spell_2', {})
 
@@ -1028,7 +1012,30 @@ func Test_spell_screendump_spellcap()
 
   " clean up
   call StopVimInTerminal(buf)
-  call delete('XtestSpellCap')
+endfunc
+
+func Test_spell_compatible()
+  CheckScreendump
+
+  let lines =<< trim END
+       call setline(1, [
+             \ "test "->repeat(20),
+             \ "",
+             \ "end",
+             \ ])
+       set spell cpo+=$
+  END
+  call writefile(lines, 'XtestSpellComp', 'D')
+  let buf = RunVimInTerminal('-S XtestSpellComp', {'rows': 8})
+
+  call term_sendkeys(buf, "51|C")
+  call VerifyScreenDump(buf, 'Test_spell_compatible_1', {})
+
+  call term_sendkeys(buf, "x")
+  call VerifyScreenDump(buf, 'Test_spell_compatible_2', {})
+
+  " clean up
+  call StopVimInTerminal(buf)
 endfunc
 
 let g:test_data_aff1 = [