Is a plea agreement relevant impeachment evidence that must be disclosed to the defense?

"[T]he existence of a plea agreement is relevant impeachment evidence that must be disclosed to the defense because it bears on the witness's credibility. [Citation.] Indeed, . . . `when an accomplice testifies for the prosecution, full disclosure of any agreement affecting the witness is required to ensure that the jury has a complete picture of the factors affecting the witness's credibility.' [Citation.]" (People v. Fauber, supra, 2 Cal.4th at p. 821; see also People v. Phillips (1985) 41 Cal.3d 29, 46.)