In Leone v. Medical Board (2000) 22 Cal.4th 660the Supreme Court distinguished "writ petitions challenging pretrial superior court rulings that could also be reviewed on appeal from the judgment ultimately entered in the action" from "situations in which a writ petition was the only authorized mode of appellate review." As to the former, the Court explained, "'When the court denies a writ petition without issuing an alternative writ, it does not take jurisdiction over the case; it does not give the legal issue full plenary review.'" (Leone v. Medical Board, supra, 22 Cal.4th at pp. 669-670.) However, when a writ petition constitutes the exclusive means of obtaining appellate review of an order, "an appellate court must judge the petition on its procedural and substantive merits, and a summary denial of the petition is necessarily on the merits." (Id. at p. 670.)