I'm not ready for my current employer to know about this, so I've created a throwaway account to ask about it.

A week ago I interviewed with Google, and I just got the feedback: they're very happy and want to move forward. They've sent me an email asking for various details, including my current salary.

Now it seems to me very much as if I don't want to tell them my current salary - I suspect I'd do much better if they worked out what they felt I was worth to them and offered me that, rather than taking my current salary and adding a bit extra. The Internet is full of advice that you shouldn't tell a prospective employer your current salary when they ask. But I'm suspicious of this advice - it seems like the sort of thing they would say whether it was true or not. What's your guess - in real life, how offputting is it for an employer if a candidate refuses to disclose that kind of detail when you ask for it as part of your process? How likely are Google to be put off by it?