From 994728b5ed76571f2f7c4c73197cc2e0f1b3ff74 Mon Sep 17 00:00:00 2001
From: Joseph Doherty <dohejw01@gmail.com>
Date: Sun, 26 Apr 2026 17:05:29 -0400
Subject: [PATCH] refactor: open_db with check_same_thread parameter (T68)

---
 chat/db/connection.py           |  4 +--
 chat/web/bots.py                | 11 ++-----
 tests/test_open_db_threading.py | 57 +++++++++++++++++++++++++++++++++
 3 files changed, 61 insertions(+), 11 deletions(-)
 create mode 100644 tests/test_open_db_threading.py

diff --git a/chat/db/connection.py b/chat/db/connection.py
index ad21a01..f293aca 100644
--- a/chat/db/connection.py
+++ b/chat/db/connection.py
@@ -5,9 +5,9 @@ from pathlib import Path
 
 
 @contextmanager
-def open_db(path: Path):
+def open_db(path: Path, *, check_same_thread: bool = True):
     path.parent.mkdir(parents=True, exist_ok=True)
-    conn = sqlite3.connect(path)
+    conn = sqlite3.connect(path, check_same_thread=check_same_thread)
     conn.execute("PRAGMA journal_mode=WAL")
     conn.execute("PRAGMA foreign_keys=ON")
     try:
diff --git a/chat/web/bots.py b/chat/web/bots.py
index d9666f3..027130b 100644
--- a/chat/web/bots.py
+++ b/chat/web/bots.py
@@ -1,10 +1,10 @@
 from __future__ import annotations
-import sqlite3
 from pathlib import Path
 from fastapi import APIRouter, Depends, Form, HTTPException, Request
 from fastapi.responses import RedirectResponse, HTMLResponse
 from fastapi.templating import Jinja2Templates
 
+from chat.db.connection import open_db
 from chat.eventlog.log import append_event
 from chat.eventlog.projector import project
 from chat.state.entities import list_bots
@@ -19,15 +19,8 @@ REQUIRED_FIELDS = ("id", "name", "persona", "initial_relationship_to_you", "kick
 def get_conn(request: Request):
     settings = request.app.state.settings
     db_path: Path = settings.db_path
-    db_path.parent.mkdir(parents=True, exist_ok=True)
-    conn = sqlite3.connect(db_path, check_same_thread=False)
-    conn.execute("PRAGMA journal_mode=WAL")
-    conn.execute("PRAGMA foreign_keys=ON")
-    try:
+    with open_db(db_path, check_same_thread=False) as conn:
         yield conn
-        conn.commit()
-    finally:
-        conn.close()
 
 
 def _split_voice_samples(text: str) -> list[str]:
diff --git a/tests/test_open_db_threading.py b/tests/test_open_db_threading.py
new file mode 100644
index 0000000..c7756f9
--- /dev/null
+++ b/tests/test_open_db_threading.py
@@ -0,0 +1,57 @@
+from __future__ import annotations
+import sqlite3
+import threading
+
+from chat.db.connection import open_db
+
+
+def test_open_db_default_uses_check_same_thread_true(tmp_path):
+    """Default open_db must reject cross-thread use (safe default)."""
+    db = tmp_path / "t.db"
+    captured: list[BaseException | None] = []
+
+    with open_db(db) as conn:
+        conn.execute("CREATE TABLE t (x INTEGER)")
+
+        def worker():
+            try:
+                conn.execute("SELECT 1").fetchall()
+                captured.append(None)
+            except BaseException as e:  # noqa: BLE001
+                captured.append(e)
+
+        t = threading.Thread(target=worker)
+        t.start()
+        t.join()
+
+    assert len(captured) == 1
+    err = captured[0]
+    assert isinstance(err, sqlite3.ProgrammingError), (
+        f"expected sqlite3.ProgrammingError on cross-thread use, got {err!r}"
+    )
+
+
+def test_open_db_can_disable_check_same_thread(tmp_path):
+    """open_db(check_same_thread=False) must allow cross-thread use."""
+    db = tmp_path / "t.db"
+    captured: list[BaseException | None] = []
+    rows: list[object] = []
+
+    with open_db(db, check_same_thread=False) as conn:
+        conn.execute("CREATE TABLE t (x INTEGER)")
+        conn.execute("INSERT INTO t (x) VALUES (42)")
+
+        def worker():
+            try:
+                result = conn.execute("SELECT x FROM t").fetchall()
+                rows.extend(result)
+                captured.append(None)
+            except BaseException as e:  # noqa: BLE001
+                captured.append(e)
+
+        t = threading.Thread(target=worker)
+        t.start()
+        t.join()
+
+    assert captured == [None], f"worker thread raised: {captured}"
+    assert rows == [(42,)]