What is the test for disclosing confidential information in a criminal case?

Notably, "[i]t is incumbent on the defendant to make a prima facie showing for disclosure before an in camera hearing is appropriate. [Citation.] [] Disclosure is mandated only when the defendant, upon whom the burden falls, produces ' "some evidence" [citation]' [citation] to show ' "a reasonable possibility that the anonymous informant whose identity is sought could give evidence on the issue of guilt which might result in defendant's exoneration." [Citations.]' [Citation.]" (People v. Oppel (1990) 222 Cal.App.3d 1146, 1152; People v. Fried (1989) 214 Cal.App.3d 1309, 1314-1315 [an in camera hearing is not required "if an informant is not shown to be in a position to give possible testimony which will aid the defendant on the issue of guilt. The mere assertion that the informant is a material witness on that issue, without any plausible support therefor, does not trigger the requirements of the statute."].)