A person born to an Indonesian citizen parent acquires Indonesian citizenship under Law No. 12 of 2006. Birth in Indonesia alone to two foreign parents is not general jus soli.
Sources: Indonesia Law No. 12 of 2006 on Citizenship (English text)
A legally married foreign spouse acquires nationality by declaration rather than presidential-discretion naturalization.
Sources: Indonesia Law No. 12 of 2006 on Citizenship (English text)
A child acquires Indonesian citizenship when a parent is an Indonesian citizen under the lineage rules of Law No. 12 of 2006, including specified mixed-nationality and acknowledgment situations. Limited dual citizenship for children ends when the child must choose nationality at majority or marriage.
Sources: Indonesia Law No. 12 of 2006 on Citizenship (English text)
A foreign adult (or married applicant) may request naturalization after residing in Indonesian territory for at least five consecutive years or at least ten years intermittently, with capacity, Indonesian language ability, acceptance of Pancasila and the Constitution, good health, no serious criminal conviction, livelihood, payment of the statutory fee, and no dual citizenship upon becoming Indonesian. Approval is discretionary at the presidential level after ministerial process.
Sources: Indonesia Law No. 12 of 2006 on Citizenship (English text) · Direktorat Jenderal Imigrasi — official portal