Fix tag clear hang

Author: HexDecimal

CHANGELOG.md

@@ -7,6 +7,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Fixed
+
+- Clearing an entity with inherited tags no longer hangs.
+
 ## [5.2.2] - 2024-08-03
 
 ### Fixed

tcod/ecs/entity.py

@@ -650,6 +650,12 @@ def remove(self, tag: object) -> None:
             raise KeyError(tag)
         self.discard(tag)
 
+    def clear(self) -> None:
+        """Remove all tags directly in this entity."""
+        _tags_by_entity = self.entity.registry._tags_by_entity
+        while _tags_by_entity[self.entity]:
+            self.discard(next(iter(_tags_by_entity[self.entity])))
+
     def __contains__(self, x: object) -> bool:
         """Return True if this entity has the given tag."""
         _tags_by_entity = self.entity.registry._tags_by_entity

tests/test_traversal.py

@@ -205,3 +205,13 @@ def test_relation_traversal() -> None:
     assert len(world["C"].relation_components[str]) == 2  # noqa: PLR2004
     world["C"].relation_components[int][world["foo"]] = 0
     assert set(world["C"].relation_components) == {str, int}
+
+
+def test_inherited_clear() -> None:
+    world = Registry()
+    world["A"].components[int] = 1
+    world["A"].tags.add("foo")
+    world["A"].relation_components[str][world["B"]] = "bar"
+    world["A"].relation_tags["baz"] = world["B"]
+    child = world["A"].instantiate()
+    child.clear()  # Could hang if broken