lib/streamlit/elements/widgets/time_widgets.py:498

• This new _to_date helper duplicates the existing _convert_datelike_to_date logic in this module (which already converts datetime to date). Reusing _convert_datelike_to_date would reduce duplication and keep date normalization behavior centralized.

def _to_date(v: date) -> date:
    """Convert datetime to date for comparison.

    st.date_input can receive datetime values from session_state. Since datetime
    is a subclass of date, isinstance(v, date) returns True, but datetime and date
    objects cannot be directly compared with < or >. This helper normalizes the
    value for safe comparison with date bounds.
    """
    return v.date() if isinstance(v, datetime) else v

lib/streamlit/elements/widgets/time_widgets.py:557

• _validate_date_value now normalizes datetime values only for bound comparisons, but it can still return a datetime unchanged when the current value comes from session_state. That’s inconsistent with st.date_input’s documented behavior of ignoring the time component and returning a datetime.date. Consider normalizing current_value (and range tuple entries) to date before returning/updating session_state so the widget’s return type matches its API contract.

    elif not parsed_values.is_range and isinstance(current_value, date):
        # For single date mode. Use _to_date to handle datetime values from session_state.
        if (
            _to_date(current_value) < parsed_values.min
            or _to_date(current_value) > parsed_values.max
        ):
            value_needs_reset = True

lib/tests/streamlit/elements/date_input_test.py:1046

• The in-test import from datetime import datetime as dt is redundant since datetime is already imported at module scope, and it goes against the test-file pattern of keeping imports at the top. Consider removing this local import and using the existing module-level datetime import instead.

    from datetime import datetime as dt

lib/tests/streamlit/elements/date_input_test.py:1069

• The test asserts that st.date_input preserves a datetime value from st.session_state, but the public API docstring says date_input ignores any time component and returns datetime.date. This assertion also diverges from existing tests that expect a date when a datetime is provided as value. Consider asserting the returned value is the corresponding date (and/or that no exception is raised) rather than locking in a datetime return type here.

    assert not at.exception
    # The widget preserves the datetime type from session_state
    assert at.date_input[0].value == dt(2025, 6, 15, 12, 30, 0)