sudden coderabbit review fixes

src/wf_core/models/reducers.py

@@ -8,6 +8,11 @@ from pydantic import BaseModel, ConfigDict, Field, model_validator
 from wf_platform.refs import CapabilityRef
 
 
+def _raise_conflicting_ref_and_name() -> None:
+    """Reject ambiguous reducer references before compatibility coercion."""
+    raise ValueError("reducer ref and name are mutually exclusive")
+
+
 class ReducerRef(BaseModel):
     """Reference to one reducer capability plus JSON-compatible configuration."""
 
@@ -28,6 +33,8 @@ class ReducerRef(BaseModel):
         `ReducerRef(name="wf.std.add")`. That remains source-compatible, but
         the model state is now the structural capability reference.
         """
+        if ref is not None and name is not None:
+            _raise_conflicting_ref_and_name()
         payload: dict[str, object] = {"config": config or {}}
         if ref is not None:
             payload["ref"] = ref
@@ -45,6 +52,8 @@ class ReducerRef(BaseModel):
         if not isinstance(value, Mapping):
             return value
         data = dict(value)
+        if "ref" in data and "name" in data:
+            _raise_conflicting_ref_and_name()
         if "ref" not in data and "name" in data:
             data["ref"] = CapabilityRef.parse(str(data.pop("name")))
         return data

src/wf_core/paths.py

@@ -406,6 +406,8 @@ def get_nested_value(state: Mapping[str, Any], path_parts: list[str]) -> Any:
 def set_nested_value(
     state: MutableMapping[str, Any], path_parts: list[str], value: Any
 ) -> None:
+    if not path_parts:
+        raise PathResolutionError("cannot set value with empty path")
     current: MutableMapping[str, Any] = state
     for part in path_parts[:-1]:
         next_value = current.get(part)

src/wf_core/run_state.py

@@ -93,7 +93,14 @@ class RunState:
     def current_frame(self) -> ExecutionFrame:
         if self.current_frame_id is None:
             raise ValueError("run has no current frame")
-        return self.frames[self.current_frame_id]
+        frame = self.frames.get(self.current_frame_id)
+        if frame is None:
+            raise ValueError(
+                "run current frame id is missing from frames: "
+                f"current_frame_id={self.current_frame_id!r}, "
+                f"frames={sorted(self.frames)!r}"
+            )
+        return frame
 
     def sync_from_current_frame(self) -> None:
         frame = self.current_frame()

src/wf_core/runtime/engine.py

@@ -27,7 +27,7 @@ def execute_workflow(
     run = create_run_state(workflow, workflow_input)
 
     try:
-        run = prepare_new_run(workflow, workflow_input)
+        prepare_new_run(workflow, workflow_input, run)
         return resume_workflow(workflow, run, registry, reducers=reducers)
     except Exception as exc:
         run.status = RunStatus.FAILED
@@ -46,7 +46,7 @@ async def execute_workflow_async(
     run = create_run_state(workflow, workflow_input)
 
     try:
-        run = prepare_new_run(workflow, workflow_input)
+        prepare_new_run(workflow, workflow_input, run)
         return await resume_workflow_async(workflow, run, registry, reducers=reducers)
     except Exception as exc:
         run.status = RunStatus.FAILED

src/wf_core/runtime/preparation.py

@@ -9,15 +9,17 @@ from wf_core.runtime.ops.frames import collapse_completed_frames
 from wf_core.runtime.ops.index import WorkflowIndex, build_workflow_index
 from wf_core.runtime.ops.interrupts import resume_interrupt
 from wf_core.runtime.ops.merges import ReducerDefinition
-from wf_core.runtime.ops.runs import create_run_state
 from wf_core.runtime.ops.schemas import validate_payload_against_schema
 from wf_core.run_state import FrameStatus, RunState, RunStatus
 from wf_core.tokens import END
 
 
-def prepare_new_run(workflow: Workflow, workflow_input: dict[str, Any]) -> RunState:
+def prepare_new_run(
+    workflow: Workflow,
+    workflow_input: dict[str, Any],
+    run: RunState,
+) -> RunState:
     """Create and validate a fresh run state for a workflow invocation."""
-    run = create_run_state(workflow, workflow_input)
     workflow.validate_structure().raise_for_errors()
     validate_payload_against_schema(
         workflow.input_schema, workflow_input, "workflow input"

tests/core/test_nested_state_paths.py

@@ -1,5 +1,7 @@
 from __future__ import annotations
 
+import pytest
+
 from wf_core import (
     ReducerRef,
     ReducerSpec,
@@ -354,6 +356,22 @@ def test_reducer_ref_accepts_canonical_ref_object() -> None:
     assert reducer.name == "wf.std.append"
 
 
+def test_reducer_ref_rejects_conflicting_ref_and_name() -> None:
+    with pytest.raises(ValueError, match="mutually exclusive"):
+        ReducerRef(
+            ref={"source": "wf.std", "capability_key": "append"},
+            name="wf.std.add",
+        )
+
+    with pytest.raises(ValueError, match="mutually exclusive"):
+        ReducerRef.model_validate(
+            {
+                "ref": {"source": "wf.std", "capability_key": "append"},
+                "name": "wf.std.add",
+            }
+        )
+
+
 def test_unknown_state_reducer_fails_clearly() -> None:
     workflow = _workflow(
         fields={

tests/core/test_path_values.py

@@ -11,6 +11,7 @@ from wf_core.paths import (
     StatePath,
     is_valid_destination_path,
     is_valid_source_path,
+    set_nested_value,
 )
 
 
@@ -254,3 +255,8 @@ def test_existing_source_and_destination_validation_helpers_use_new_parsers() ->
     assert is_valid_destination_path("state") is False
     assert is_valid_destination_path("state.person") is True
     assert is_valid_destination_path("input.person") is False
+
+
+def test_set_nested_value_rejects_empty_path() -> None:
+    with pytest.raises(PathResolutionError, match="empty path"):
+        set_nested_value({}, [], "value")

tests/core/test_run_state.py

@@ -0,0 +1,18 @@
+from __future__ import annotations
+
+import pytest
+
+from wf_core.run_state import RunState, RunStatus
+
+
+def test_current_frame_rejects_missing_frame_id_with_clear_error() -> None:
+    run = RunState(
+        workflow_name="demo",
+        status=RunStatus.RUNNING,
+        workflow_input={},
+        state={},
+        current_frame_id="missing",
+    )
+
+    with pytest.raises(ValueError, match="current_frame_id='missing'"):
+        run.current_frame()