Map API fix: avoid destroying map value upon update with same value pointer.

Author: FedeDP

Lib/map.c

@@ -181,7 +181,7 @@ static map_ret_code hashmap_put(map_t *m, const char *key, void *value) {
     if (!entry->key) {
         entry->key = key;
         m->length++;
-    } else if (m->dtor) {
+    } else if (m->dtor && entry->data != value) {
         /* Destroy old value if needed */
         m->dtor(entry->data);
     }

TODO.md

@@ -42,6 +42,7 @@ conversely to module_stop that should stop module right away freeing all its enq
 - [x] Set keydup and autofree in map_new()
 - [x] Drop map_set_dtor
 - [x] Destroy old value upon val update
+- [x] Avoid destroying map value on update with same pointer; just return MAP_OK
 
 ### Stack
 - [x] stack->dtor should default to memhook._free, and fallback to default if stack_set_dtor is called with NULL callback parameter