Resolve all deferred audit findings: type safety, async, isolation, dates

- #11 VectorIndexProtocol for typed duck-typing of vector_index param
- #10 Wrap all sync VectorIndex.query() calls in asyncio.to_thread
- #9 Make vector_search async (consistent with to_thread wrapping)
- #12 Replace module-level singleton with app.state.query_service
- #13 InMemoryGraphDB.close(destroy=False) guard for test safety
- #14 Parse dates with datetime.fromisoformat in list_cases sort

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

aucourt_ingest/api/app.py

@@ -6,7 +6,6 @@ from contextlib import asynccontextmanager
 
 from fastapi import FastAPI
 
-from aucourt_ingest.api import dependencies
 from aucourt_ingest.api.errors import register_error_handlers
 from aucourt_ingest.api.routes import router
 from aucourt_ingest.api.service import QueryService
@@ -21,7 +20,7 @@ def create_app(graph_db: GraphDB, vector_index, max_tokens: int = 4000) -> FastA
         vector_index: VectorIndex instance (or duck-typed fake for tests)
         max_tokens: Default token budget for juror context assembly
     """
-    dependencies._query_service = QueryService(graph_db, vector_index, max_tokens)
+    query_service = QueryService(graph_db, vector_index, max_tokens)
 
     @asynccontextmanager
     async def lifespan(app: FastAPI):
@@ -35,6 +34,7 @@ def create_app(graph_db: GraphDB, vector_index, max_tokens: int = 4000) -> FastA
         lifespan=lifespan,
     )
 
+    app.state.query_service = query_service
     app.include_router(router)
     register_error_handlers(app)
 

aucourt_ingest/api/dependencies.py

@@ -2,12 +2,13 @@
 
 from __future__ import annotations
 
+from fastapi import Request
+
 from aucourt_ingest.api.service import QueryService
 
-_query_service: QueryService | None = None
 
-
-def get_query_service() -> QueryService:
-    if _query_service is None:
+def get_query_service(request: Request) -> QueryService:
+    svc = request.app.state.query_service
+    if svc is None:
         raise RuntimeError("QueryService not initialised — call create_app() first")
-    return _query_service
+    return svc

aucourt_ingest/api/routes.py

@@ -80,7 +80,7 @@ async def vector_search(
 ):
     types = [t.strip() for t in chunk_types.split(",") if t.strip()] if chunk_types else None
     docs = [d.strip() for d in doc_ids.split(",") if d.strip()] if doc_ids else None
-    return svc.vector_search(q, top_k=top_k, chunk_types=types, doc_ids=docs)
+    return await svc.vector_search(q, top_k=top_k, chunk_types=types, doc_ids=docs)
 
 
 @router.get("/hybrid", response_model=list[HybridResult])

aucourt_ingest/api/service.py

@@ -2,7 +2,10 @@
 
 from __future__ import annotations
 
+import asyncio
 import logging
+from datetime import datetime
+from typing import Protocol, runtime_checkable
 
 from aucourt_ingest.jury.personas import PERSONAS, get_persona
 from aucourt_ingest.jury.subgraph_query import SubgraphQuery
@@ -11,10 +14,26 @@ from aucourt_ingest.storage.graph_db import GraphDB
 logger = logging.getLogger(__name__)
 
 
+@runtime_checkable
+class VectorIndexProtocol(Protocol):
+    """Protocol for VectorIndex — used for type-safe duck-typing."""
+
+    def query(self, text: str, top_k: int = 10,
+              chunk_types: list[str] | None = None,
+              doc_ids: list[str] | None = None,
+              embedding: list[float] | None = None) -> list[dict]:
+        ...
+
+    @property
+    def count(self) -> int:
+        ...
+
+
 class QueryService:
     """Read-only query service for juror RAG queries."""
 
-    def __init__(self, graph_db: GraphDB, vector_index, max_tokens: int = 4000):
+    def __init__(self, graph_db: GraphDB, vector_index: VectorIndexProtocol,
+                 max_tokens: int = 4000):
         self._graph_db = graph_db
         self._vector_index = vector_index
         self._subgraph = SubgraphQuery(graph_db)
@@ -46,11 +65,11 @@ class QueryService:
                 "matter_type": node.properties.get("matter_type", ""),
                 "verdict": node.properties.get("verdict", ""),
             })
-        cases.sort(key=lambda c: c.get("date", ""), reverse=True)
+        cases.sort(key=lambda c: _parse_date_key(c.get("date", "")), reverse=True)
         return cases[offset:offset + limit]
 
     async def search_cases(self, q: str, limit: int = 10) -> list[dict]:
-        results = self._vector_index.query(q, top_k=limit)
+        results = await asyncio.to_thread(self._vector_index.query, q, top_k=limit)
         seen: set[str] = set()
         cases = []
         for r in results:
@@ -73,17 +92,21 @@ class QueryService:
             "total_tokens": ctx.total_tokens,
         }
 
-    def vector_search(self, query: str, top_k: int = 10,
-                       chunk_types: list[str] | None = None,
-                       doc_ids: list[str] | None = None) -> list[dict]:
-        return self._vector_index.query(
-            query, top_k=top_k, chunk_types=chunk_types, doc_ids=doc_ids,
+    async def vector_search(self, query: str, top_k: int = 10,
+                            chunk_types: list[str] | None = None,
+                            doc_ids: list[str] | None = None) -> list[dict]:
+        results = await asyncio.to_thread(
+            self._vector_index.query, query,
+            top_k=top_k, chunk_types=chunk_types, doc_ids=doc_ids,
         )
+        return results
 
     async def hybrid_search(self, query: str, persona_name: str | None = None,
                               top_k: int = 10,
                               max_tokens: int | None = None) -> list[dict]:
-        vector_results = self._vector_index.query(query, top_k=top_k)
+        vector_results = await asyncio.to_thread(
+            self._vector_index.query, query, top_k=top_k,
+        )
         # Group by doc_id
         by_doc: dict[str, list[dict]] = {}
         for r in vector_results:
@@ -190,3 +213,13 @@ def _rel_to_dict(rel) -> dict:
         "rel_type": rel.rel_type,
         "properties": rel.properties,
     }
+
+
+def _parse_date_key(date_str: str) -> datetime | None:
+    """Parse ISO 8601 date string for sorting. Returns None for empty/invalid."""
+    if not date_str:
+        return None
+    try:
+        return datetime.fromisoformat(date_str[:10])
+    except (ValueError, IndexError):
+        return None

aucourt_ingest/storage/in_memory_graph_db.py

@@ -103,7 +103,9 @@ class InMemoryGraphDB:
         except (nx.NetworkXNoPath, nx.NodeNotFound):
             return None
 
-    async def close(self):
-        self._g.clear()
-        self._nodes.clear()
-        self._rels.clear()
+    async def close(self, destroy: bool = True):
+        """Clear graph data. Set destroy=False to keep data (e.g. for tests)."""
+        if destroy:
+            self._g.clear()
+            self._nodes.clear()
+            self._rels.clear()