work_entry_source_field

The widget extends the standard radio field and adds two getters:

get isFullyFlexible() {
    return !this.props.record.data.resource_calendar_id;
}

get tooltipWarning() {
    return JSON.stringify({
        "text" : _t("Invalid option: For fully flexible calendars, the work entry source cannot be 'Working Hours'."),
    })
}

An employee with no resource_calendar_id has no fixed schedule, so there are no working hours for a work entry to be generated from. The widget detects that and surfaces a warning.

It declares the calendar as a field dependency, which means the check works even when that field is not placed on the form. The dependency is fetched for the widget's own use.

This is a small but instructive piece of design. The rule it encodes is a payroll rule, and payroll rules are exactly the kind that produce a confusing server error at save time if the interface does not mention them.

Rather than blocking the option or throwing, the widget warns. The user can still see the choice and understand why it will not work, which is usually better than an option that silently vanishes.

If you build payroll or attendance screens, that pattern is worth keeping even though the widget is not.

On a work entry source field in Odoo 19:

<field name="work_entry_source" widget="work_entry_source_field"/>

The employee's calendar does not need to be on the form, because the widget declares it as a dependency:

fieldDependencies: [
    { name: "resource_calendar_id", type: "many2one", relation: "resource.calendar" },
],

Removed. The registration is absent from the 20.0 branch.

Odoo 20 does register a work_entry_type_badge widget in the same area, but it is not a replacement: it renders a work entry type as a badge rather than offering a source choice with a validity warning. Treat it as a neighboring widget, not a migration target.

If the flexible-calendar rule matters to your payroll setup, the warning has to move somewhere. A Python constraint will enforce it at save; reproducing the inline warning needs a small custom widget extending radio, which is all this one ever was.