Does the need for a full factual record apply in reviewing legal issues concerning the admissibility of a confession obtained in violation of the Constitution?

However, the first consideration, the need for a full factual record, does not apply in reviewing legal issues concerning the admissibility of confessions obtained in violation of the Constitution. Although a challenge to an improperly admitted prior felony conviction involves factual determinations, [42 Cal.App.4th 471] the trial court and the reviewing court can determine whether a constitutional violation occurred based on the evidence presented in a motion to suppress. (Adkins, supra, 791 F.2d at p. 594.) Thus, a full record for resolving the issue does not depend upon the defendant's having testified. This court has discretion to decide a pure question of law based on undisputed facts. (Hale v. Morgan (1978) 22 Cal.3d 388, 394, 149 Cal.Rptr. 375, 584 P.2d 512.)