patch 8.2.2420: too many problems with using all autocommand events

Problem:    Too many problems with using all autocommand events.
Solution:   Disallow defining an autocommand for all events.

src/autocmd.c

@@ -956,6 +956,9 @@ do_autocmd(char_u *arg_in, int forceit)
     last_group = AUGROUP_ERROR;		// for listing the group name
     if (*arg == '*' || *arg == NUL || *arg == '|')
     {
+	if (!forceit && *cmd != NUL)
+	    emsg(_(e_cannot_define_autocommands_for_all_events));
+	else
 	    for (event = (event_T)0; (int)event < (int)NUM_EVENTS;
 					     event = (event_T)((int)event + 1))
 		if (do_autocmd_event(event, pat,

src/errors.h

@@ -345,3 +345,5 @@ EXTERN char e_invalid_operation_for_bool[]
 	INIT(= N_("E1153: Invalid operation for bool"));
 EXTERN char e_divide_by_zero[]
 	INIT(= N_("E1154: Divide by zero"));
+EXTERN char e_cannot_define_autocommands_for_all_events[]
+	INIT(= N_("E1155: Cannot define autocommands for ALL events"));

src/testdir/test_autocmd.vim

@@ -1827,20 +1827,9 @@ func Test_TextYankPost()
   bwipe!
 endfunc
 
-func Test_nocatch_wipe_all_buffers()
-  " Real nasty autocommand: wipe all buffers on any event.
-  au * * bwipe *
-  call assert_fails('next x', ['E94:', 'E937:'])
-  bwipe
-  au!
-endfunc
-
-func Test_nocatch_wipe_dummy_buffer()
-  CheckFeature quickfix
-  " Nasty autocommand: wipe buffer on any event.
-  au * x bwipe
-  call assert_fails('lv½ /x', 'E937:')
-  au!
+func Test_autocommand_all_events()
+  call assert_fails('au * * bwipe', 'E1155:')
+  call assert_fails('au * x bwipe', 'E1155:')
 endfunc
 
 function s:Before_test_dirchanged()

src/testdir/test_quickfix.vim

@@ -3833,7 +3833,7 @@ func Test_lbuffer_crash()
   sv Xtest
   augroup QF_Test
     au!
-    au * * bw
+    au QuickFixCmdPre,QuickFixCmdPost,BufEnter,BufLeave * bw
   augroup END
   lbuffer
   augroup QF_Test
@@ -3845,7 +3845,7 @@ endfunc
 func Test_lexpr_crash()
   augroup QF_Test
     au!
-    au * * call setloclist(0, [], 'f')
+    au QuickFixCmdPre,QuickFixCmdPost,BufEnter,BufLeave * call setloclist(0, [], 'f')
   augroup END
   lexpr ""
   augroup QF_Test
@@ -3880,7 +3880,7 @@ func Test_lvimgrep_crash()
   sv Xtest
   augroup QF_Test
     au!
-    au * * call setloclist(0, [], 'f')
+    au QuickFixCmdPre,QuickFixCmdPost,BufEnter,BufLeave * call setloclist(0, [], 'f')
   augroup END
   lvimgrep quickfix test_quickfix.vim
   augroup QF_Test
@@ -4215,7 +4215,7 @@ func Test_lbuffer_with_bwipe()
   new
   new
   augroup nasty
-    au * * bwipe
+    au QuickFixCmdPre,QuickFixCmdPost,BufEnter,BufLeave * bwipe
   augroup END
   lbuffer
   augroup nasty
@@ -4228,9 +4228,9 @@ endfunc
 func Xexpr_acmd_freelist(cchar)
   call s:setup_commands(a:cchar)
 
-  " This was using freed memory.
+  " This was using freed memory (but with what events?)
   augroup nasty
-    au * * call g:Xsetlist([], 'f')
+    au QuickFixCmdPre,QuickFixCmdPost,BufEnter,BufLeave * call g:Xsetlist([], 'f')
   augroup END
   Xexpr "x"
   augroup nasty

src/testdir/test_window_cmd.vim

@@ -567,8 +567,8 @@ endfunc
 
 func Test_access_freed_mem()
   call assert_equal(&columns, winwidth(0))
-  " This was accessing freed memory
-  au * 0 vs xxx
+  " This was accessing freed memory (but with what events?)
+  au BufEnter,BufLeave,WinEnter,WinLeave 0 vs xxx
   arg 0
   argadd
   call assert_fails("all", "E242:")

src/version.c

@@ -750,6 +750,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    2420,
 /**/
     2419,
 /**/