Merge pull request #2901 from orestisf1993/issue-2900

Set marks to NULL after freeing

src/load_layout.c

@@ -157,6 +157,7 @@ static int json_end_map(void *ctx) {
             }
 
             free(marks);
+            marks = NULL;
             num_marks = 0;
         }
 

testcases/t/267-regress-mark-restart.t

@@ -20,6 +20,8 @@ use i3test;
 
 cmd 'open';
 cmd 'mark foo';
+cmd 'open';
+cmd 'mark bar';
 
 cmd 'restart';