What is the test for a defendant's self-defense defense in a criminal case?

A trial court in a criminal case has a duty to instruct, sua sponte, on general principles closely and openly connected with the facts of the case, including potential defenses. (People v. Breverman (1998) 19 Cal.4th 142, 154.) However, the duty to give sua sponte instructions on a particular defense arises only if (1) it appears that the defendant is relying on such a defense or (2) if there is substantial evidence supportive of such a defense and the defense is not inconsistent with the defendant's theory of the case. (Id. at p. 157; People v. Barton (1995) 12 Cal.4th 186, 197.)

The People respond that self-defense (and implicitly the related theory of excessive force used by a victim⁴) are not defenses to a charge of robbery as a matter of law, a contention that does have precedential support. (People v. Costa (1963) 218 Cal.App.2d 310, 316; see generally People v. Gomez (2008) 43 Cal.4th 249, 264 [recognizing that a victim who sees his property being stolen may reasonably be expected to try to reclaim the property and that "[i]t is the conduct of the perpetrator who resorts to violence to further his theft, . . . not the decision of the victim to confront the perpetrator" that is relevant to the determination of whether a robbery occurred].) However, even if we assume that the case law establishes a general rule that may be subject to exceptions

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