patch 8.2.2472: crash when using command line window in an autocommand

Problem:    Crash when using command line window in an autocommand.
            (houyunsong)
Solution:   Save and restore au_new_curbuf.

Author: brammool

src/ex_cmds.c

@@ -2710,8 +2710,9 @@ do_ecmd(
 	 */
 	if (buf != curbuf)
 	{
+	    bufref_T	save_au_new_curbuf;
 #ifdef FEAT_CMDWIN
-	    int save_cmdwin_type = cmdwin_type;
+	    int		save_cmdwin_type = cmdwin_type;
 
 	    // BufLeave applies to the old buffer.
 	    cmdwin_type = 0;
@@ -2728,6 +2729,7 @@ do_ecmd(
 	     */
 	    if (buf->b_fname != NULL)
 		new_name = vim_strsave(buf->b_fname);
+	    save_au_new_curbuf = au_new_curbuf;
 	    set_bufref(&au_new_curbuf, buf);
 	    apply_autocmds(EVENT_BUFLEAVE, NULL, NULL, FALSE, curbuf);
 #ifdef FEAT_CMDWIN
@@ -2737,12 +2739,14 @@ do_ecmd(
 	    {
 		// new buffer has been deleted
 		delbuf_msg(new_name);	// frees new_name
+		au_new_curbuf = save_au_new_curbuf;
 		goto theend;
 	    }
 #ifdef FEAT_EVAL
 	    if (aborting())	    // autocmds may abort script processing
 	    {
 		vim_free(new_name);
+		au_new_curbuf = save_au_new_curbuf;
 		goto theend;
 	    }
 #endif
@@ -2778,6 +2782,7 @@ do_ecmd(
 		if (aborting() && curwin->w_buffer != NULL)
 		{
 		    vim_free(new_name);
+		    au_new_curbuf = save_au_new_curbuf;
 		    goto theend;
 		}
 #endif
@@ -2786,6 +2791,7 @@ do_ecmd(
 		{
 		    // new buffer has been deleted
 		    delbuf_msg(new_name);	// frees new_name
+		    au_new_curbuf = save_au_new_curbuf;
 		    goto theend;
 		}
 		if (buf == curbuf)		// already in new buffer
@@ -2831,8 +2837,7 @@ do_ecmd(
 #endif
 	    }
 	    vim_free(new_name);
-	    au_new_curbuf.br_buf = NULL;
-	    au_new_curbuf.br_buf_free_count = 0;
+	    au_new_curbuf = save_au_new_curbuf;
 	}
 
 	curwin->w_pcmark.lnum = 1;

src/testdir/test_autocmd.vim

@@ -2739,9 +2739,9 @@ func Test_autocmd_closes_window()
   au BufNew,BufWinLeave * e %e
   file yyy
   au BufNew,BufWinLeave * ball
-  call assert_fails('n xxx', 'E143:')
+  n xxx
 
-  bwipe %
+  %bwipe
   au! BufNew
   au! BufWinLeave
 endfunc
@@ -2759,4 +2759,19 @@ func Test_autocmd_quit_psearch()
   augroup END
 endfunc
 
+" Fuzzer found some strange combination that caused a crash.
+func Test_autocmd_normal_mess()
+  augroup aucmd_normal_test
+    au BufLeave,BufWinLeave,BufHidden,BufUnload,BufDelete,BufWipeout * norm 7q/qc
+  augroup END
+  o4
+  silent! H
+  e xx
+  normal G
+
+  augroup aucmd_normal_test
+    au!
+  augroup END
+endfunc
+
 " vim: shiftwidth=2 sts=2 expandtab

src/version.c

@@ -750,6 +750,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    2472,
 /**/
     2471,
 /**/