vim-patch:8.2.3940: match highlight disappears when doing incsearch for ":s/pat"

Problem:    Match highlight disappears when doing incsearch for ":s/pat".
Solution:   Only use line limit for incsearch highlighting. (closes vim/vim#9425)

94fb8274ca

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

src/nvim/match.c

@@ -425,7 +425,7 @@ static void next_search_hl(win_T *win, match_T *search_hl, match_T *shl, linenr_
   const int called_emsg_before = called_emsg;
 
   // for :{range}s/pat only highlight inside the range
-  if (lnum < search_first_line || lnum > search_last_line) {
+  if ((lnum < search_first_line || lnum > search_last_line) && cur == NULL) {
     shl->lnum = 0;
     return;
   }

src/nvim/testdir/test_match.vim

@@ -380,6 +380,27 @@ func Test_match_in_linebreak()
   call delete('XscriptMatchLinebreak')
 endfunc
 
+func Test_match_with_incsearch()
+  CheckRunVimInTerminal
+
+  let lines =<< trim END
+    set incsearch
+    call setline(1, range(20))
+    call matchaddpos('ErrorMsg', [3])
+  END
+  call writefile(lines, 'XmatchWithIncsearch')
+  let buf = RunVimInTerminal('-S XmatchWithIncsearch', #{rows: 6})
+  call TermWait(buf)
+  call VerifyScreenDump(buf, 'Test_match_with_incsearch_1', {})
+
+  call term_sendkeys(buf, ":s/0")
+  call VerifyScreenDump(buf, 'Test_match_with_incsearch_2', {})
+
+  call term_sendkeys(buf, "\<CR>")
+  call StopVimInTerminal(buf)
+  call delete('XmatchWithIncsearch')
+endfunc
+
 " Test for deleting matches outside of the screen redraw top/bottom lines
 " This should cause a redraw of those lines.
 func Test_matchdelete_redraw()

test/functional/legacy/match_spec.lua

@@ -2,6 +2,7 @@ local helpers = require('test.functional.helpers')(after_each)
 local Screen = require('test.functional.ui.screen')
 local clear = helpers.clear
 local exec = helpers.exec
+local feed = helpers.feed
 
 before_each(clear)
 
@@ -64,4 +65,36 @@ describe('match highlighting', function()
                                                                                  |
     ]])
   end)
+
+  it('is shown with incsearch vim-patch:8.2.3940', function()
+    local screen = Screen.new(75, 6)
+    screen:set_default_attr_ids({
+      [0] = {bold = true, foreground = Screen.colors.Blue},  -- NonText
+      [1] = {background = Screen.colors.Yellow},  -- Search
+      [2] = {background = Screen.colors.Red, foreground = Screen.colors.White},  -- ErrorMsg
+    })
+    screen:attach()
+    exec([[
+      set incsearch
+      call setline(1, range(20))
+      call matchaddpos('ErrorMsg', [3])
+    ]])
+    screen:expect([[
+      ^0                                                                          |
+      1                                                                          |
+      {2:2}                                                                          |
+      3                                                                          |
+      4                                                                          |
+                                                                                 |
+    ]])
+    feed(':s/0')
+    screen:expect([[
+      {1:0}                                                                          |
+      1                                                                          |
+      {2:2}                                                                          |
+      3                                                                          |
+      4                                                                          |
+      :s/0^                                                                       |
+    ]])
+  end)
 end)