handle datetime conversion better

Author: imryche

.sql-formatter.json

@@ -0,0 +1,4 @@
+{
+  "language": "sqlite",
+  "keywordCase": "lower"
+}

litequery/core.py

@@ -6,7 +6,7 @@
 from collections.abc import Iterator
 from contextlib import contextmanager
 from dataclasses import dataclass
-from datetime import datetime
+from datetime import UTC, datetime
 from enum import Enum
 from pathlib import Path
 from typing import Any
@@ -38,19 +38,9 @@ def __init__(self, columns: list[str], values: list[Any]):
             dups = [c for c in columns if columns.count(c) > 1]
             raise ValueError(f"Duplicate columns: {set(dups)}. Use AS to alias.")
 
-        self._values = tuple(
-            self._parse_datetime(v) if isinstance(v, str) else v for v in values
-        )
+        self._values = values
         self._index = {c: i for i, c in enumerate(columns)}
 
-    def _parse_datetime(self, value: str):
-        if 19 <= len(value) <= 32 and value[0].isdigit():
-            try:
-                return datetime.fromisoformat(value)
-            except ValueError:
-                pass
-        return value
-
     def _available_columns(self) -> str:
         return ", ".join([f"'{c}'" for c in self._index.keys()])
 
@@ -154,6 +144,16 @@ def row_factory(cursor, row):
     return Row(columns, row)
 
 
+def adapt_datetime(value: datetime):
+    if value.tzinfo:
+        value = value.astimezone(UTC)
+    return value.replace(tzinfo=None).isoformat(sep=" ")
+
+
+def convert_datetime(value: bytes):
+    return datetime.fromisoformat(value.decode())
+
+
 class Litequery:
     PRAGMAS = [
         ("journal_mode", "wal"),
@@ -169,11 +169,15 @@ def __init__(self, config: Config, queries):
         self._thread_local = threading.local()
         self._create_methods(queries)
 
+        sqlite3.register_adapter(datetime, adapt_datetime)
+        sqlite3.register_converter("datetime", convert_datetime)
+
     def _create_connection(self) -> sqlite3.Connection:
         conn = sqlite3.connect(
             self.config.database_path,
             timeout=30,
             autocommit=True,
+            detect_types=sqlite3.PARSE_COLNAMES | sqlite3.PARSE_DECLTYPES,
         )
         conn.row_factory = row_factory
         pragmas = (f"PRAGMA {p} = {v}" for p, v in self.PRAGMAS)

tests/queries/users.sql

@@ -1,29 +1,30 @@
 -- name: get_all_users
 select
-    *
+  *
 from
-    users;
+  users;
 
 -- name: get_user_by_id^
 select
-    *
+  *
 from
-    users
+  users
 where
-    id = :id;
+  id = :id;
 
 -- name: get_last_user_id$
 select
-    id
+  id
 from
-    users
+  users
 order by
-    id desc;
+  id desc;
 
 -- name: insert_user<!
-insert into users (name, email)
-    values (:name, :email);
+insert into
+  users (name, email)
+values
+  (:name, :email);
 
 -- name: delete_all_users!
 delete from users;
-

tests/test_conversions.py

@@ -0,0 +1,27 @@
+from datetime import UTC, datetime, timedelta, timezone
+
+
+def test_naive_datetime_roundtrip(lq):
+    dt = datetime(2025, 10, 24, 9, 30, 0, 0)
+    row = lq.raw_one("select :dt as 'dt [datetime]'", dt=dt)
+
+    assert isinstance(row.dt, datetime)
+    assert row.dt.tzinfo is None
+    assert row.dt == dt
+
+
+def test_aware_datetime_converts_to_utc_naive(lq):
+    tz = timezone(timedelta(hours=5))
+    dt = datetime(2024, 1, 2, 10, 0, 0, tzinfo=tz)
+    row = lq.raw_one("select :dt as 'dt [datetime]'", dt=dt)
+
+    dt_normalized = dt.astimezone(UTC).replace(tzinfo=None)
+    assert row.dt.tzinfo is None
+    assert row.dt == dt_normalized
+
+
+def test_datetime_column_is_naive(lq):
+    user = lq.get_user_by_id(id=1)
+
+    assert isinstance(user.created_at, datetime)
+    assert user.created_at.tzinfo is None