even MORE code review

stateful to not deadhang, graph context -> output, more explicit state errors, other misc changes idfk any of those good thing theyre fixed tho

tests/core/test_foreach_barrier_state.py

@@ -10,6 +10,7 @@ from wf_core.runtime.foreach_state import (
     ForeachBarrierState,
     ItemErrorRecord,
     PendingItemResult,
+    _state_write_from_metadata,
 )
 from wf_core.runtime.lineage import LineageStateView, lineage_writes_for_frame
 from wf_core.runtime.ops.state import StatePatch
@@ -88,6 +89,21 @@ def test_foreach_barrier_state_round_trips_reducer_write_records() -> None:
     assert write.reducer.name == "wf.std.add"
 
 
+def test_pending_write_metadata_preserves_invalid_reducer_detail() -> None:
+    with pytest.raises(WorkflowExecutionError, match="mutually exclusive"):
+        _state_write_from_metadata(
+            {
+                "path": {"root": "state", "parts": ["count"]},
+                "incoming_value": 1,
+                "visible_value": 1,
+                "reducer": {
+                    "name": "wf.std.add",
+                    "ref": {"source": "wf.std", "capability_key": "add"},
+                },
+            }
+        )
+
+
 def test_lineage_state_view_materializes_visible_values_without_mutating_base() -> None:
     base_state = {"count": 2, "nested": {"value": "old"}}
     view = LineageStateView(

tests/core/test_lineage_state.py

@@ -1,5 +1,7 @@
 from __future__ import annotations
 
+import pytest
+
 from wf_core import (
     END,
     Edge,
@@ -9,6 +11,7 @@ from wf_core import (
     StateField,
     StateSchema,
     Workflow,
+    WorkflowExecutionError,
 )
 from wf_core.models.reducers import ReducerRef
 from wf_core.paths import StatePath
@@ -158,6 +161,14 @@ def test_state_view_for_frame_overlays_writes_onto_frame_scope_state() -> None:
     assert run.state["value"] == "root"
 
 
+def test_lineage_state_view_rejects_corrupt_parent_cycle() -> None:
+    run = create_run_state(_minimal_workflow(), {"value": "root"})
+    run.lineages["root"].parent_id = "root"
+
+    with pytest.raises(WorkflowExecutionError, match="cycle"):
+        lineage_state_view(run, scope_id="root", lineage_id="root")
+
+
 def test_lineage_state_view_handles_deep_ancestry_without_recursion() -> None:
     run = create_run_state(_minimal_workflow(), {"value": "root"})
     parent_id = "root"

tests/core/test_subgraph_step.py

@@ -24,8 +24,9 @@ from wf_core import (
     resume_workflow_async,
     resume_workflow,
 )
+from wf_core.models.steps import InputPathBinding, Step
+from wf_core.paths import GraphSourcePath, LocalPath
 from wf_core.validation.issues import ValidationIssueCode
-from wf_core.models.steps import Step
 
 
 def test_subgraph_step_validates_boundary_bindings_and_outcomes() -> None:
@@ -158,6 +159,34 @@ def test_subgraph_step_executes_caller_prepared_saved_child_ref() -> None:
     assert run.trace[-1].step_type == "subgraph"
 
 
+def test_subgraph_step_projects_child_context_output() -> None:
+    child = Workflow(
+        name="context_child",
+        input_schema=_schema({"text": {"type": "string"}}),
+        state_schema=StateSchema.from_field_map({}),
+        output_schema=_schema({"answer": {"type": "string"}}),
+        output=[
+            InputPathBinding(
+                target=LocalPath.of("answer"),
+                path=GraphSourcePath.parse("context.scope_id"),
+            )
+        ],
+        outcomes=["ok"],
+        start="done",
+        nodes=[EndNode(id="done", type="end", outcome="ok")],
+        edges=[],
+    )
+
+    run = execute_workflow(
+        _workflow(output_schema=_schema({"answer": {"type": "string"}})),
+        {"text": "hello"},
+        {},
+        subgraphs={"child.workflow": PreparedSubgraph(workflow=child, registry={})},
+    )
+
+    assert run.output["answer"] == "root:subgraph:child"
+
+
 def test_subgraph_step_executes_prepared_async_child() -> None:
     async def answer(payload: dict[str, object], _ctx: object) -> dict[str, object]:
         return {"answer": f"async:{payload['text']}"}