California Code, Health and Safety Code - HSC § 11370

(a) A person convicted of violating Section 11353 or 11361, or of committing an offense referred to in those sections, shall not, except as provided in subdivision (e), be granted probation by the trial court or have the execution of the sentence suspended by the court, if the person has been previously convicted of an offense described in subdivision (c).

(b) A person who was 18 years of age or older at the time of the commission of the offense and is convicted for the first time of selling, furnishing, administering, or giving a controlled substance that is (1) specified in subdivision (b), (c), (e), or paragraph (1) of subdivision (f) of Section 11054, specified in paragraph (14), (15), or (20) of subdivision (d) of Section 11054, or specified in subdivision (b) or (c) of Section 11055, or (2) that is a narcotic drug classified in Schedule III, IV, or V, to a minor or inducing a minor to use the controlled substance in violation of law shall not, except as provided in subdivision (e), be granted probation by the trial court or have the execution of the sentence suspended by the court.

(c) A previous conviction of any of the following offenses, or of an offense under the laws of another state or of the United States that, if committed in this state, would have been punishable as that offense, shall render a person ineligible for probation or suspension of sentence pursuant to subdivision (a):

(d) The existence of a previous conviction or fact that would make a person ineligible for suspension of sentence or probation under this section shall be alleged in the information or indictment, and either admitted by the defendant in open court, or found to be true by the jury trying the issue of guilt or by the court where guilt is established by a plea of guilty or nolo contendere or by trial by the court sitting without a jury.

(e) A person who is made ineligible for probation pursuant to this section may be granted probation only in an unusual case where the interests of justice would best be served. When probation is granted pursuant to this subdivision, the court shall specify on the record the circumstances supporting the finding.