Handle going from location=None to unset and back in prototype, as per #2005

evennia/prototypes/menus.py

@@ -2294,7 +2294,8 @@ def node_apply_diff(caller, **kwargs):
     if not custom_location:
         diff.pop("location", None)
 
-    txt, options = _format_diff_text_and_options(diff, objects=update_objects, base_obj=base_obj)
+    txt, options = _format_diff_text_and_options(diff, objects=update_objects,
+                                                 base_obj=base_obj, prototype=prototype)
 
     if options:
         text = [

evennia/prototypes/prototypes.py

@@ -272,10 +272,10 @@ def save_prototype(prototype):
         stored_prototype = create_script(
             DbPrototype,
             key=prototype_key,
-            desc=prototype["prototype_desc"],
+            desc=in_prototype["prototype_desc"],
             persistent=True,
             locks=prototype_locks,
-            tags=prototype["prototype_tags"],
+            tags=in_prototype["prototype_tags"],
             attributes=[("prototype", in_prototype)],
         )
     return stored_prototype.prototype
@@ -724,15 +724,15 @@ def prototype_to_str(prototype):
         prototype_desc=prototype.get("prototype_desc", "|wNone|n"),
         prototype_parent=prototype.get("prototype_parent", "|wNone|n"),
     )
-
-    key = prototype.get("key", "")
-    if key:
+    key = aliases = attrs = tags = locks = permissions = location = home = destination = ""
+    if "key" in prototype:
+        key = prototype["key"]
         key = "|ckey:|n {key}".format(key=key)
-    aliases = prototype.get("aliases", "")
-    if aliases:
+    if "aliases" in prototype:
+        aliases = prototype["aliases"]
         aliases = "|caliases:|n {aliases}".format(aliases=", ".join(aliases))
-    attrs = prototype.get("attrs", "")
-    if attrs:
+    if "attrs" in prototype:
+        attrs = prototype["attrs"]
         out = []
         for (attrkey, value, category, locks) in attrs:
             locks = ", ".join(lock for lock in locks if lock)
@@ -751,8 +751,8 @@ def prototype_to_str(prototype):
                 )
             )
         attrs = "|cattrs:|n\n {attrs}".format(attrs="\n ".join(out))
-    tags = prototype.get("tags", "")
-    if tags:
+    if "tags" in prototype:
+        tags = prototype['tags']
         out = []
         for (tagkey, category, data) in tags:
             out.append(
@@ -761,20 +761,20 @@ def prototype_to_str(prototype):
                 )
             )
         tags = "|ctags:|n\n {tags}".format(tags=", ".join(out))
-    locks = prototype.get("locks", "")
-    if locks:
+    if "locks" in prototype:
+        locks = prototype["locks"]
         locks = "|clocks:|n\n {locks}".format(locks=locks)
-    permissions = prototype.get("permissions", "")
-    if permissions:
+    if "permissions" in prototype:
+        permissions = prototype["permissions"]
         permissions = "|cpermissions:|n {perms}".format(perms=", ".join(permissions))
-    location = prototype.get("location", "")
-    if location:
+    if "location" in prototype:
+        location = prototype["location"]
         location = "|clocation:|n {location}".format(location=location)
-    home = prototype.get("home", "")
-    if home:
+    if "home" in prototype:
+        home = prototype["home"]
         home = "|chome:|n {home}".format(home=home)
-    destination = prototype.get("destination", "")
-    if destination:
+    if "destination" in prototype:
+        destination = prototype["destination"]
         destination = "|cdestination:|n {destination}".format(destination=destination)
 
     body = "\n".join(

evennia/prototypes/spawner.py

@@ -354,6 +354,9 @@ def prototype_diff(prototype1, prototype2, maxdepth=2, homogenize=False, implici
     class Unset:
         def __bool__(self):
             return False
+        def __str__(self):
+            return "<Unset>"
+
     _unset = Unset()
 
     def _recursive_diff(old, new, depth=0):
@@ -361,10 +364,10 @@ def prototype_diff(prototype1, prototype2, maxdepth=2, homogenize=False, implici
         old_type = type(old)
         new_type = type(new)
 
-        if old_type == new_type and not (old and new):
+        if old_type == new_type and not (old or new):
             # both old and new are unset, like [] or None
-            return (old, new, "KEEP")
-        elif old_type != new_type:
+            return (None, None, "KEEP")
+        if old_type != new_type:
             if old and not new:
                 if depth < maxdepth and old_type == dict:
                     return {key: (part, None, "REMOVE") for key, part in old.items()}
@@ -388,7 +391,7 @@ def prototype_diff(prototype1, prototype2, maxdepth=2, homogenize=False, implici
         elif depth < maxdepth and new_type == dict:
             all_keys = set(list(old.keys()) + list(new.keys()))
             return {
-                key: _recursive_diff(old.get(key), new.get(key, _unset), depth=depth + 1)
+                key: _recursive_diff(old.get(key, _unset), new.get(key, _unset), depth=depth + 1)
                 for key in all_keys
             }
         elif depth < maxdepth and is_iter(new):
@@ -396,7 +399,7 @@ def prototype_diff(prototype1, prototype2, maxdepth=2, homogenize=False, implici
             new_map = {part[0] if is_iter(part) else part: part for part in new}
             all_keys = set(list(old_map.keys()) + list(new_map.keys()))
             return {
-                key: _recursive_diff(old_map.get(key), new_map.get(key, _unset), depth=depth + 1)
+                key: _recursive_diff(old_map.get(key, _unset), new_map.get(key, _unset), depth=depth + 1)
                 for key in all_keys
             }
         elif old != new: