patch 8.0.1413: accessing freed memory in :cbuffer

Problem:    Accessing freed memory in :cbuffer.
Solution:   Get quickfix list after executing autocmds. (closes #2470)

Author: brammool

src/quickfix.c

@@ -5520,14 +5520,6 @@ ex_cbuffer(exarg_T *eap)
 #endif
     int		res;
 
-    if (eap->cmdidx == CMD_lbuffer || eap->cmdidx == CMD_lgetbuffer
-	    || eap->cmdidx == CMD_laddbuffer)
-    {
-	qi = ll_get_or_alloc_list(curwin);
-	if (qi == NULL)
-	    return;
-    }
-
 #ifdef FEAT_AUTOCMD
     switch (eap->cmdidx)
     {
@@ -5549,6 +5541,15 @@ ex_cbuffer(exarg_T *eap)
     }
 #endif
 
+    /* Must come after autocommands. */
+    if (eap->cmdidx == CMD_lbuffer || eap->cmdidx == CMD_lgetbuffer
+	    || eap->cmdidx == CMD_laddbuffer)
+    {
+	qi = ll_get_or_alloc_list(curwin);
+	if (qi == NULL)
+	    return;
+    }
+
     if (*eap->arg == NUL)
 	buf = curbuf;
     else if (*skipwhite(skipdigits(eap->arg)) == NUL)

src/testdir/test_autocmd.vim

@@ -1178,3 +1178,10 @@ func Test_nocatch_wipe_dummy_buffer()
   call assert_fails('lv½ /x', 'E480')
   au!
 endfunc
+
+func Test_wipe_cbuffer()
+  sv x
+  au * * bw
+  lb
+  au!
+endfunc

src/version.c

@@ -771,6 +771,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1413,
 /**/
     1412,
 /**/