How to work with an overly positive advisor? I'm in my second year of my PhD and my advisor is very, very positive. She never gives me negative feedback, even when I objectively have made a mistake. 

For instance, two months ago, I noticed that I had made a mistake in my code that invalidated about 6 months of work. She wasn't even mad, saying things like "everyone makes mistakes" and "we can fix this." I was able to redo the analysis and still find interesting results, so it did more or less work out. But this is just one example of how positive she is. 

Last year she encouraged me to apply to an university internal poster session and strongly suggested that it was highly probable that I would win one of the prizes offered. I did not win, nor do I feel like I was that close to winning. I was a first year student competing against fourth and fifth years. 

Additionally, she is always happy with whatever I present to her. I'll admit, some weeks I do not produce much work, sometimes I'm slow to give her abstracts to review for conferences, etc, but she is always happy with whatever I give her. 

She praises me excessively for every little thing, no matter how good or bad. She says "excellent work, great job, you're making fantastic progress." I get the same exact level of praise on the weeks I do a lot of work and weeks I do little work. 

I'm used to working with PIs were much more blunt. Not necessarily negative, but told me how I was doing. If I didn't do much work, they would say "that's all you've done?" However, if I actually did a good job, I would get a "good job" or something. 

It's very hard for me to manage my expectations with my advisor. I don't know if I am actually doing a good job or not. I don't know what my approximate actual chances are for awards and acceptances to conferences. 

I'm afraid to ask her to be more blunt, because I'm afraid she would completely switch and criticize me too much. 

How can I manage my expectations and work better with my perpetually positive professor?
I sympathize with this because I had an overly positive advisor for approximately 3.5 years, until I was getting ready to go on the job market and then suddenly he had tons of problems with my work. Others have told you to go elsewhere for criticism. This is probably a good idea, but you should also be able to have a good, balanced discussion with your main advisor who knows your work best.

Two things might be helpful:

1) Ask her what criticisms a reviewer might have of your approach to X

2) Ask her what needs to be done to improve Y

The first may help because she may be able to get in a different mindset about criticism if she is asked to think about the paper like a reviewer (a reviewer's "job" is to be critical, but she may feel that an advisor's "job" is to be encouraging). The second may help because it invites her to frame problems in an encouraging, positive way (which seems to be her comfort zone).