fix: update RunResult to track current turn number and ensure it is preserved during state conversion

Author: mjschock

src/agents/result.py

@@ -159,6 +159,8 @@ class RunResult(RunResultBase):
     _current_turn_persisted_item_count: int = 0
     """Number of items from new_items already persisted to session for the
     current turn."""
+    _current_turn: int = 0
+    """The current turn number. This is preserved when converting to RunState."""
     _original_input: str | list[TResponseInputItem] | None = field(default=None, repr=False)
     """The original input from the first turn. Unlike `input`, this is never updated during the run.
     Used by to_state() to preserve the correct originalInput when serializing state."""
@@ -229,6 +231,7 @@ def to_state(self) -> Any:
         state._input_guardrail_results = self.input_guardrail_results
         state._output_guardrail_results = self.output_guardrail_results
         state._last_processed_response = self._last_processed_response
+        state._current_turn = self._current_turn
         state._current_turn_persisted_item_count = self._current_turn_persisted_item_count
         state.set_tool_use_tracker_snapshot(self._tool_use_tracker_snapshot)
 

src/agents/run.py

@@ -1241,6 +1241,7 @@ def _get_approval_identity(
                                     ),
                                     max_turns=max_turns,
                                 )
+                                result._current_turn = current_turn
                                 result._original_input = _copy_str_or_list(original_input)
                                 return result
 
@@ -1286,6 +1287,7 @@ def _get_approval_identity(
                                     ),
                                     max_turns=max_turns,
                                 )
+                                result._current_turn = current_turn
                                 if server_conversation_tracker is None:
                                     # Save both input and output items together at the end.
                                     # When resuming from state, session_input_items_for_save
@@ -1651,6 +1653,7 @@ def _get_approval_identity(
                                 ),
                                 max_turns=max_turns,
                             )
+                            result._current_turn = current_turn
                             if run_state is not None:
                                 result._current_turn_persisted_item_count = (
                                     run_state._current_turn_persisted_item_count
@@ -1706,6 +1709,7 @@ def _get_approval_identity(
                                 ),
                                 max_turns=max_turns,
                             )
+                            result._current_turn = current_turn
                             if run_state is not None:
                                 result._current_turn_persisted_item_count = (
                                     run_state._current_turn_persisted_item_count