patch 8.0.1408: crash in setqflist()

Problem:    Crash in setqflist().
Solution:   Check for string to be NULL. (Dominique Pelle, closes #2464)

Author: brammool

src/quickfix.c

@@ -4930,8 +4930,9 @@ qf_get_properties(win_T *wp, dict_T *what, dict_T *retdict)
 			qf_idx = -1;
 		}
 	    }
-	    else if ((di->di_tv.v_type == VAR_STRING)
-		    && (STRCMP(di->di_tv.vval.v_string, "$") == 0))
+	    else if (di->di_tv.v_type == VAR_STRING
+			    && di->di_tv.vval.v_string != NULL
+			    && STRCMP(di->di_tv.vval.v_string, "$") == 0)
 		/* Get the last quickfix list number */
 		qf_idx = qi->qf_listcount - 1;
 	    else
@@ -5226,7 +5227,8 @@ qf_set_properties(qf_info_T *qi, dict_T *what, int action, char_u *title)
 		newlist = FALSE;	/* use the specified list */
 	}
 	else if (di->di_tv.v_type == VAR_STRING
-		&& STRCMP(di->di_tv.vval.v_string, "$") == 0)
+			&& di->di_tv.vval.v_string != NULL
+			&& STRCMP(di->di_tv.vval.v_string, "$") == 0)
 	{
 	    if (qi->qf_listcount > 0)
 		qf_idx = qi->qf_listcount - 1;

src/testdir/test_quickfix.vim

@@ -1428,6 +1428,11 @@ func XquickfixSetListWithAct(cchar)
   call assert_fails("call g:Xsetlist(list1, 0)", 'E928:')
 endfunc
 
+func Test_setqflist_invalid_nr()
+  " The following command used to crash Vim
+  call setqflist([], ' ', {'nr' : $XXX_DOES_NOT_EXIST})
+endfunc
+
 func Test_quickfix_set_list_with_act()
   call XquickfixSetListWithAct('c')
   call XquickfixSetListWithAct('l')
@@ -2946,6 +2951,15 @@ func Test_getqflist()
   call Xgetlist_empty_tests('l')
 endfunc
 
+func Test_getqflist_invalid_nr()
+  " The following commands used to crash Vim
+  cexpr ""
+  call getqflist({'nr' : $XXX_DOES_NOT_EXIST_XXX})
+
+  " Cleanup
+  call setqflist([], 'r')
+endfunc
+
 " Tests for the quickfix/location list changedtick
 func Xqftick_tests(cchar)
   call s:setup_commands(a:cchar)

src/version.c

@@ -771,6 +771,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1408,
 /**/
     1407,
 /**/