even more code review

src/wf_core/runtime/ops/nodes.py

@@ -154,10 +154,11 @@ def execute_node_use(
             f"no handler registered for node def {node.node!r}"
         )
 
+    frame = run.current_frame()
     resolved_input, context, state_view = _resolve_node_execution(
         workflow=workflow,
         run=run,
-        frame=run.current_frame(),
+        frame=frame,
         node=node,
         node_def=node_def,
     )
@@ -165,7 +166,7 @@ def execute_node_use(
     return _finalize_node_execution(
         workflow=workflow,
         run=run,
-        frame=run.current_frame(),
+        frame=frame,
         node=node,
         node_def=node_def,
         resolved_input=resolved_input,
@@ -189,10 +190,11 @@ async def execute_node_use_async(
             f"no handler registered for node def {node.node!r}"
         )
 
+    frame = run.current_frame()
     resolved_input, context, state_view = _resolve_node_execution(
         workflow=workflow,
         run=run,
-        frame=run.current_frame(),
+        frame=frame,
         node=node,
         node_def=node_def,
     )
@@ -204,7 +206,7 @@ async def execute_node_use_async(
     return _finalize_node_execution(
         workflow=workflow,
         run=run,
-        frame=run.current_frame(),
+        frame=frame,
         node=node,
         node_def=node_def,
         resolved_input=resolved_input,

src/wf_core/runtime/ops/overlays.py

@@ -30,6 +30,8 @@ def state_view_for_frame(run: RunState, frame: ExecutionFrame) -> dict[str, Any]
     if pending is None:
         return run.state
 
+    # Correctness first: this full copy isolates sibling reads. If state grows
+    # large, replace this with a lazy/copy-on-write overlay.
     state_view = deepcopy(run.state)
     for destination, value in pending.patch.changes.items():
         path = StatePath.parse(destination)

src/wf_core/runtime/scheduler.py

@@ -111,18 +111,18 @@ def enqueue_frame(run: RunState, frame_id: str, *, front: bool = False) -> None:
 
 def select_next_frame(run: RunState) -> ExecutionFrame | None:
     """Select the next ready frame and update compatibility cursor fields."""
-    while run.ready_frame_ids:
-        frame_id = run.ready_frame_ids.pop(0)
-        frame = _frame(run, frame_id)
-        if frame.status != FrameStatus.PENDING:
-            raise WorkflowExecutionError(
-                f"ready frame {frame_id!r} has status {frame.status!s}"
-            )
-        frame.status = FrameStatus.RUNNING
-        run.current_frame_id = frame.id
-        run.sync_from_current_frame()
-        return frame
-    return None
+    if not run.ready_frame_ids:
+        return None
+    frame_id = run.ready_frame_ids.pop(0)
+    frame = _frame(run, frame_id)
+    if frame.status != FrameStatus.PENDING:
+        raise WorkflowExecutionError(
+            f"ready frame {frame_id!r} has status {frame.status!s}"
+        )
+    frame.status = FrameStatus.RUNNING
+    run.current_frame_id = frame.id
+    run.sync_from_current_frame()
+    return frame
 
 
 def mark_frame_pending(run: RunState, frame_id: str, *, front: bool = False) -> None:

src/wf_core/runtime/step.py

@@ -237,7 +237,7 @@ async def _step_async_foreach_item_batch(
     """Run one batch of ready concurrent-foreach item node handlers.
 
     Only handler awaits run concurrently. Finalization, tracing, and frame
-    advancement happen afterward in frame-id order so `RunState` is mutated
+    advancement happen afterward in ready-queue order so `RunState` is mutated
     deterministically.
     """
     frames = [first_frame, *_claim_matching_async_item_frames(run, index, first_frame)]