This is an historical aberration. However, I have a shock for you - and the entire Hindutva brigade.
Goa already has a uniform civil code.
Please consider the different situations in Great Britain, actually, in England and Wales, since Scots law differs in certain particulars, and in France.
England followed common law, a system whereby all law is either statutory, regulatory or case law. If a matter is defined by law passed in a legislature, it is governed by statutory law. If a regulatory authority determines certain processes and functions to be undertaken, based on its authority from the legislature, it is regulatory law that determines it. If neither, then case law is used. Case law is nothing but the study of precedents set in previous cases. In south Asia, both Pakistan and India follow common law, but Sri Lanka follows civil law, since the Dutch introduced European law to the country, and Goa follows civil law due to the Portuguese occupation. Common law covers civil law, everything related to property and to contracts, and criminal law, obviously, crimes.
However, personal matters such as birth, marriage, divorce, sharing of family property and inheritance are covered by Personal Laws. The Hindus are under Mitakshara throughout India, except for Bengal, which is under Dayabhaga. Muslims are under different laws for Sunni and Shia; Indian Muslims are under Hanafi or Jafari systems, depending on whether Sunni or Shia. Christians are governed under the Indian statutes of marriage, divorce, adoption, inheritance, and guardianship. Brahmos are under the special marriage act. Jains, Buddhists and Sikhs, for historical reasons, are under the Hindu laws, specifically, under the Hindu marriage act.
I am prepared to explain further, but only if anyone is interested.