What is the test for determining whether a plea bargain is valid?

Turning to the merits, our review of the terms of a plea bargain is de novo when interpretation does not require examination of the credibility of extrinsic evidence. (People v. Paredes (2008) 160 Cal.App.4th 496, 507.) Resolution of credibility issues requires application of the substantial evidence test (ibid.) and we review a trial court's decision whether to grant specific performance for an abuse of discretion. (See United States v. Anthony (9th Cir. 1996) 93 F.3d 614, 616.)

"Plea bargaining is an accepted practice in American criminal procedure. [Citation.] The process is not only constitutionally permissible [citation], but has been characterized as an essential and desirable component of the administration of justice. [Citation.] Concomitant with recognition of the necessity and desirability of the process is the notion that the integrity of the process be maintained by insuring that the state keep its word when it offers inducements in exchange for a plea of guilty." (People v. Macheno (1982) 32 Cal.3d 855, 859-860.) "[W]hen a plea rests in any significant degree on a promise or agreement of the prosecutor, so that it can be said to be part of the inducement or consideration, such promise must be fulfilled." (Santobello v. New York (1971) 404 U.S. 257, 262.) When a guilty plea rests on a promise by the prosecution and that promise is violated, there is a constitutional right to a remedy. (Macheno, at p. 860.)