patch 9.0.0969: matchparen highlight is not updated when switching buffers

Problem:    Matchparen highlight is not updated when switching buffers.
Solution:   Listen to the BufLeave and the BufWinEnter autocmd events.
            (closes #11626)

runtime/plugin/matchparen.vim

@@ -1,6 +1,6 @@
 " Vim plugin for showing matching parens
 " Maintainer:  Bram Moolenaar <Bram@vim.org>
-" Last Change: 2021 Apr 08
+" Last Change: 2022 Nov 28
 
 " Exit quickly when:
 " - this plugin was already loaded (or disabled)
@@ -19,8 +19,8 @@ endif
 
 augroup matchparen
   " Replace all matchparen autocommands
-  autocmd! CursorMoved,CursorMovedI,WinEnter,WinScrolled * call s:Highlight_Matching_Pair()
+  autocmd! CursorMoved,CursorMovedI,WinEnter,BufWinEnter,WinScrolled * call s:Highlight_Matching_Pair()
-  autocmd! WinLeave * call s:Remove_Matches()
+  autocmd! WinLeave,BufLeave * call s:Remove_Matches()
   if exists('##TextChanged')
     autocmd! TextChanged,TextChangedI * call s:Highlight_Matching_Pair()
   endif

src/testdir/dumps/Test_matchparen_clear_highlight_1.dump

@@ -0,0 +1,5 @@
+>(+0&#40ffff15|)| +0&#ffffff0@72
+|~+0#4040ff13&| @73
+|~| @73
+|~| @73
+| +0#0000000&@56|1|,|1| @10|A|l@1| 

src/testdir/dumps/Test_matchparen_clear_highlight_2.dump

@@ -0,0 +1,5 @@
+>a+0&#ffffff0@1| @72
+|~+0#4040ff13&| @73
+|~| @73
+|~| @73
+| +0#0000000&@56|1|,|1| @10|A|l@1| 

src/testdir/test_display.vim

@@ -237,6 +237,37 @@ func Test_visual_block_scroll()
   call StopVimInTerminal(buf)
 endfunc
 
+" Test for clearing paren highlight when switching buffers
+func Test_matchparen_clear_highlight()
+  CheckScreendump
+
+  let lines =<< trim END
+    source $VIMRUNTIME/plugin/matchparen.vim
+    set hidden
+    call setline(1, ['()'])
+    normal 0
+
+    func OtherBuffer()
+       enew
+       exe "normal iaa\<Esc>0"
+    endfunc
+  END
+  call writefile(lines, 'XMatchparenClear', 'D')
+  let buf = RunVimInTerminal('-S XMatchparenClear', #{rows: 5})
+  call VerifyScreenDump(buf, 'Test_matchparen_clear_highlight_1', {})
+
+  call term_sendkeys(buf, ":call OtherBuffer()\<CR>:\<Esc>")
+  call VerifyScreenDump(buf, 'Test_matchparen_clear_highlight_2', {})
+
+  call term_sendkeys(buf, "\<C-^>:\<Esc>")
+  call VerifyScreenDump(buf, 'Test_matchparen_clear_highlight_1', {})
+
+  call term_sendkeys(buf, "\<C-^>:\<Esc>")
+  call VerifyScreenDump(buf, 'Test_matchparen_clear_highlight_2', {})
+
+  call StopVimInTerminal(buf)
+endfunc
+
 func Test_display_scroll_at_topline()
   CheckScreendump
 

src/version.c

@@ -695,6 +695,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    969,
 /**/
     968,
 /**/