vim-patch:9.1.1398: completion: trunc does not follow Pmenu highlighting attributes (#34084)

Problem:  When items are combined with user-defined highlight attributes
          (e.g., strikethrough), trunc inherits these attributes, making
          the text difficult to read.
Solution: trunc now uses the original Pmenu and PmenuSel highlight
          attributes (glepnir)

closes: vim/vim#17340

0816f17e9a

Co-authored-by: glepnir <glephunter@gmail.com>

test/functional/ui/popupmenu_spec.lua

@@ -5810,6 +5810,7 @@ describe('builtin popupmenu', function()
     it("'pummaxwidth' with multibyte", function()
       screen:try_resize(60, 8)
       exec([[
+        hi StrikeFake guifg=DarkRed
         let g:change = 0
         func Omni_test(findstart, base)
           if a:findstart
@@ -5834,8 +5835,14 @@ describe('builtin popupmenu', function()
               \ #{word: "bar", menu: "fooMenu", kind: "一二三四"},
               \ #{word: "一二三四五", kind: "multi"},
               \ ]
-          else
             return [#{word: "bar", menu: "fooMenu", kind: "一二三"}]
+          elseif g:change == 3
+            return [#{word: "bar", menu: "fooMenu", kind: "一二三"}]
+          else
+            return [
+              \ #{word: "一二三四五六七八九十", abbr_hlgroup: "StrikeFake"},
+              \ #{word: "123456789_123456789_123456789_", abbr_hlgroup: "StrikeFake"},
+              \ ]
           endif
         endfunc
         set omnifunc=Omni_test
@@ -6399,6 +6406,36 @@ describe('builtin popupmenu', function()
       end
       feed('<Esc>')
       command('set norightleft')
+
+      command('let g:change=4')
+      feed('S<C-X><C-O>')
+      if multigrid then
+        screen:expect({
+          grid = [[
+        ## grid 1
+          [2:--------------------------------]|*19
+          [3:--------------------------------]|
+        ## grid 2
+          一二三四五六七八九十^            |
+          {1:~                               }|*18
+        ## grid 3
+          {2:-- }{5:match 1 of 2}                 |
+        ## grid 4
+          {ds:一二三四五六七 }{s:>}|
+          {dn:123456789_12345}{n:>}|
+        ]],
+          float_pos = { [4] = { -1, 'NW', 2, 1, 0, false, 100, 1, 1, 0 } },
+        })
+      else
+        screen:expect([[
+          一二三四五六七八九十^            |
+          {ds:一二三四五六七 }{s:>}{1:                }|
+          {dn:123456789_12345}{n:>}{1:                }|
+          {1:~                               }|*16
+          {2:-- }{5:match 1 of 2}                 |
+        ]])
+      end
+      feed('<Esc>')
     end)
 
     it('does not crash when displayed in last column with rightleft #12032', function()

test/old/testdir/test_popup.vim

@@ -2036,6 +2036,7 @@ func Test_pum_maxwidth_multibyte()
   CheckScreendump
 
   let lines =<< trim END
+    hi StrikeFake ctermfg=9
     let g:change = 0
     func Omni_test(findstart, base)
       if a:findstart
@@ -2060,8 +2061,14 @@ func Test_pum_maxwidth_multibyte()
           \ #{word: "bar", menu: "fooMenu", kind: "一二三四"},
           \ #{word: "一二三四五", kind: "multi"},
           \ ]
-      else
         return [#{word: "bar", menu: "fooMenu", kind: "一二三"}]
+      elseif g:change == 3
+        return [#{word: "bar", menu: "fooMenu", kind: "一二三"}]
+      else
+        return [
+          \ #{word: "一二三四五六七八九十", abbr_hlgroup: "StrikeFake"},
+          \ #{word: "123456789_123456789_123456789_", abbr_hlgroup: "StrikeFake"},
+          \ ]
       endif
     endfunc
     set omnifunc=Omni_test
@@ -2174,6 +2181,12 @@ func Test_pum_maxwidth_multibyte()
     call term_sendkeys(buf, "\<Esc>:set norightleft\<CR>")
   endif
 
+  call term_sendkeys(buf, ":let g:change=4\<CR>")
+  call TermWait(buf, 50)
+  call term_sendkeys(buf, "S\<C-X>\<C-O>")
+  call VerifyScreenDump(buf, 'Test_pum_maxwidth_23', {'rows': 8})
+  call term_sendkeys(buf, "\<ESC>")
+
   call StopVimInTerminal(buf)
 endfunc