Mass. Gen. Laws ch. 231 § 124
Whenever a question in dispute at the trial of an issue of fact in any civil action depends upon the decision of a question of law, the appeals court or the full bench of the supreme judicial court, upon appeal may, if satisfied that it has before it all the facts necessary for determining the question in dispute, direct that judgment be entered or that such other action be taken as shall accord with the determination of such court; or if either court shall be of the opinion that it has not before it sufficient facts to determine said question, it may direct such issues or questions as it shall think proper to be tried before a jury if the case be a jury case, or otherwise before a judge, and may direct in the alternative the action to be taken upon the verdict or finding. When any such question of law shall arise in a trial, the judge shall, by leaving appropriate questions to the jury, or by his own findings where the trial is without a jury ascertain so far as is practicable all the facts both as to liability and damages necessary on any theory of the law to enable an appellate court to make the proper final disposition of the case, unless in the opinion of the court such a course is inexpedient under the circumstances of the case.
Mass. Gen. Laws ch. 231, § 124