Cal. Code of Civil Procedure § 472c

(a) When any court makes an order sustaining a demurrer without leave to amend the question as to whether or not such court abused its discretion in making such an order is open on appeal even though no request to amend such pleading was made. (b) The following orders shall be deemed open on appeal where an amended pleading is filed after the court’s order: (1) An order sustaining a demurrer to a cause of action within a complaint or cross-complaint where the order did not sustain the demurrer as to the entire complaint or cross-complaint. (2) An order sustaining a demurrer to an affirmative defense within an answer where the order sustaining the demurrer did not sustain the demurrer as to the entire answer. (3) An order granting a motion to strike a portion of a pleading where the order granting the motion to strike did not strike the entire pleading. (c) As used in this section, “open on appeal” means that a party aggrieved by an order listed in subdivision (b) may claim the order as error in an appeal from the final judgment in the action.