I agree with this. I've had everything from "here's a laptop, have fun setting everything up," to a comprehensive intro to the company and basic systems that took about half a day, along with an assigned new hire mentor and a set of starter tickets to work on for my first couple of weeks. At the first place, it took me 3 weeks to get to the point where I could submit my first pull request. At the second, I obviously wasn't fully productive right away, but I wrote real code and merged it into production within my first week.