Merge branch 'hn/submodule-comment'

* hn/submodule-comment:
submodule.c: describe submodule_to_gitdir() in a new comment

diff --combined submodule.c
index f2f30bb488c05d9002d755feed65e9ca781a440c,50bf3fb09c7ca7a890112304e96043623da5f6f5..3e3ea11761fda1c48a3cdd88e146a0f20338c364
--- 1/submodule.c
--- 2/submodule.c
+++ b/submodule.c
@@@ -1685,7 -1685,7 +1685,7 @@@ static int find_first_merges(struct obj
                        add_object_array(merges.objects[i].item, NULL, result);
        }
  
 -      free(merges.objects);
 +      object_array_clear(&merges);
        return result->nr;
  }
  
@@@ -1790,7 -1790,7 +1790,7 @@@ int merge_submodule(struct object_id *r
                        print_commit((struct commit *) merges.objects[i].item);
        }
  
 -      free(merges.objects);
 +      object_array_clear(&merges);
        return 0;
  }
  
@@@ -1997,6 -1997,10 +1997,10 @@@ const char *get_superproject_working_tr
        return ret;
  }
  
+ /*
+  * Put the gitdir for a submodule (given relative to the main
+  * repository worktree) into `buf`, or return -1 on error.
+  */
  int submodule_to_gitdir(struct strbuf *buf, const char *submodule)
  {
        const struct submodule *sub;