vim-patch:8.2.2464: using freed memory if window closed in autocommand

Problem:    Using freed memory if window closed in autocommand. (houyunsong)
Solution:   Check the window still exists.
8ab375706e

src/nvim/ex_cmds.c

@@ -2416,7 +2416,10 @@ int do_ecmd(
                      (flags & ECMD_HIDE) || curbuf->terminal ? 0 : DOBUF_UNLOAD,
                      false);
 
-        the_curwin->w_closing = false;
+        // Autocommands may have closed the window.
+        if (win_valid(the_curwin)) {
+          the_curwin->w_closing = false;
+        }
         buf->b_locked--;
 
         // autocmds may abort script processing

src/nvim/testdir/test_autocmd.vim

@@ -1939,4 +1939,15 @@ func Test_autocmd_window()
   %bw!
 endfunc
 
+func Test_autocmd_closes_window()
+  au BufNew,BufWinLeave * e %e
+  file yyy
+  au BufNew,BufWinLeave * ball
+  call assert_fails('n xxx', 'E143:')
+
+  bwipe %
+  au! BufNew
+  au! BufWinLeave
+endfunc
+
 " vim: shiftwidth=2 sts=2 expandtab