Retail giant Walmart won a legal victory Monday in a fight over taxation by Puerto Rico’s government. A federal judge in the U.S. island territory ruled that a modified tangible-property tax is invalid. The ruling was issued as Puerto Rico’s government rushes to find new sources of revenue and a debt restructuring mechanism from the U.S. Congress while struggling through a decade-long economic crisis. Gov. Alejandro Garcia Padilla said his government will appeal the decision. “The judge just took away $100 million from the people of Puerto Rico and gave it to Walmart,” he said, referring to the revenue the...