Delete part that is likely not needed anymore

Author: ilevkivskyi

mypy/dmypy_server.py

@@ -693,11 +693,10 @@ def refresh_file(module: str, path: str) -> list[str]:
 
         # Find all original modules in graph that were not reached -- they are deleted.
         to_delete = []
-        seen_and_ancestors = self._seen_and_ancestors(seen)
         for module_id in orig_modules:
             if module_id not in graph:
                 continue
-            if module_id not in seen_and_ancestors:
+            if module_id not in seen:
                 module_path = graph[module_id].path
                 assert module_path is not None
                 to_delete.append((module_id, module_path))
@@ -725,29 +724,6 @@ def refresh_file(module: str, path: str) -> list[str]:
 
         return messages
 
-    def _seen_and_ancestors(self, seen: set[str]) -> set[str]:
-        """Return the set of seen modules along with any ancestors not already in the set.
-
-        For example, given this set:
-
-            {"foo", "foo.bar", "a.b.c"}
-
-        ... we would expect this set to be returned:
-
-            {"foo", "foo.bar", "a.b.c", "a.b", "a"}
-
-        This is used to stop us from deleting ancestor modules from the graph
-        when their descendants have been seen.
-        """
-        seen_paths = seen.copy()
-        for module_path in seen:
-            while module_path := module_path.rpartition(".")[0]:
-                if module_path in seen_paths:
-                    break
-                else:
-                    seen_paths.add(module_path)
-        return seen_paths
-
     def find_reachable_changed_modules(
         self,
         roots: list[BuildSource],