Restore cursor value types before keyset filtering

Cursors are JSON, so a datetime sort key reached the next request as a
string. Tortoise's DatetimeField.to_db_value does not parse strings, so
asyncpg rejected the string where a timestamptz parameter was expected;
sqlite tolerated it, hiding the bug in tests. Coerce decoded cursor
values through their model field's to_python_value before building the
keyset filter.

server/packages/tavolo-platform/src/tavolo/platform/pagination.py

@@ -15,12 +15,15 @@ from __future__ import annotations
 import base64
 import json
 from dataclasses import dataclass
-from typing import Any, Dict, List, Optional, Tuple
+from typing import TYPE_CHECKING, Any, Dict, List, Optional, Tuple
 
 from tortoise.queryset import QuerySet
 
 from .http import extract_query_params
 
+if TYPE_CHECKING:
+    from tortoise.models import Model
+
 DEFAULT_LIMIT = 20
 MAX_LIMIT = 100
 MIN_LIMIT = 1
@@ -81,6 +84,28 @@ def parse_cursor_params(query_string: str) -> Cursor:
 Sort = List[Tuple[str, str]]
 
 
+def _coerce_sort_values(
+    model: "type[Model]", sort: Sort, after: Dict[str, Any]
+) -> Dict[str, Any]:
+    """Restore the Python type of every decoded cursor value.
+
+    The cursor is JSON, so field values travel as strings (datetimes via
+    ``default=str``). asyncpg rejects strings where a ``timestamp``
+    parameter is expected, and sqlite only tolerates them by accident, so
+    each value is run through its model field's ``to_python_value`` before
+    it reaches the keyset filter.
+    """
+    fields = model._meta.fields_map
+    coerced: Dict[str, Any] = {}
+    for field, _ in sort:
+        value = after.get(field)
+        field_obj = fields.get(field)
+        if value is not None and field_obj is not None:
+            value = field_obj.to_python_value(value)
+        coerced[field] = value
+    return coerced
+
+
 def _keyset_where(sort: Sort, after: Dict[str, Any]):
     """Build a Tortoise ``Q`` filter from a cursor."""
     from tortoise.queryset import Q  # local to keep import edge narrow
@@ -116,7 +141,8 @@ async def paginate(
         order_by.append(field if direction == "ASC" else f"-{field}")
     qs = queryset.order_by(*order_by)
     if cursor.after:
-        qs = qs.filter(_keyset_where(sort, cursor.after))
+        after = _coerce_sort_values(queryset.model, sort, cursor.after)
+        qs = qs.filter(_keyset_where(sort, after))
     rows = await qs.limit(cursor.limit + 1)
     if len(rows) <= cursor.limit:
         return rows, None

server/packages/tavolo-platform/tests/test_pagination.py

@@ -0,0 +1,81 @@
+"""Keyset pagination tests: cursor values are restored to Python types.
+
+Cursors are JSON, so a cursor carrying a datetime reaches the next
+request as a string. Postgres/asyncpg rejects strings for timestamp
+parameters (sqlite silently coerces them), so ``paginate`` must run the
+decoded values through their model fields before building the WHERE
+clause.
+"""
+from __future__ import annotations
+
+import unittest
+import uuid
+from datetime import datetime, timezone
+from typing import Any, List
+
+from tavolo.platform.models import Match
+from tavolo.platform.pagination import Cursor, decode_cursor, encode_cursor, paginate
+
+from helpers import async_test
+
+SORT = [("finished_at", "DESC"), ("id", "ASC")]
+
+
+class _CapturingQuerySet:
+    """Minimal stand-in for a Tortoise QuerySet, recording its filter."""
+
+    model = Match
+
+    def __init__(self) -> None:
+        self.queryset_filter: Any = None
+
+    def order_by(self, *orderings: str) -> "_CapturingQuerySet":
+        return self
+
+    def filter(self, q: Any) -> "_CapturingQuerySet":
+        self.queryset_filter = q
+        return self
+
+    async def limit(self, count: int) -> List[Any]:
+        return []
+
+
+def _flatten_q(q: Any) -> List[Any]:
+    nodes = [q]
+    for child in q.children:
+        nodes.extend(_flatten_q(child))
+    return nodes
+
+
+def _filter_values(q: Any, key: str) -> List[Any]:
+    return [node.filters[key] for node in _flatten_q(q) if key in node.filters]
+
+
+class PaginateCursorTypesTest(unittest.TestCase):
+    @async_test
+    async def test_cursor_values_are_restored_before_filtering(self) -> None:
+        match_id = uuid.uuid4()
+        finished_at = datetime(2026, 9, 19, 5, 2, 50, 547904, tzinfo=timezone.utc)
+        # Round-trip through the wire format, exactly as a request does.
+        after = decode_cursor(
+            encode_cursor({"finished_at": finished_at, "id": match_id})
+        )
+        assert after is not None
+
+        qs = _CapturingQuerySet()
+        await paginate(qs, SORT, Cursor(limit=1, after=after))
+
+        assert qs.queryset_filter is not None
+        for key in ("finished_at", "finished_at__lt"):
+            values = _filter_values(qs.queryset_filter, key)
+            self.assertEqual(1, len(values))
+            self.assertIsInstance(values[0], datetime)
+            self.assertEqual(finished_at, values[0])
+        id_values = _filter_values(qs.queryset_filter, "id__gt")
+        self.assertEqual(1, len(id_values))
+        self.assertIsInstance(id_values[0], uuid.UUID)
+        self.assertEqual(match_id, id_values[0])
+
+
+if __name__ == "__main__":
+    unittest.main()