// TODO: Refactor allowErrors logic so that it's actually part of the internal $getProperty implementation in dlayer itself, and this abstraction uses that tool?
// The AllowErrors option is set when a source definition has its own way to deal with (allowable) errors. Instead of simply propagating the error for all affected attributes, it calls the attribute handlers with the Result (or returns `undefined` if only a property is specified).
// TODO: Change implementation to allow `Result.ok(null|undefined)` but not `null|undefined` directly?
thrownewError(`Null-ish result returned for ID ${util.inspect(properties[ID])} from source '${source}'; this is not allowed, and there is probably a bug in your code. Please file a ticket if you have a good usecase for null-ish results!`);
// NOTE: We always specify the generated properties first, so that properties can be overridden by explicit known values to bypass the source lookup, if needed by the implementation