NaN and +/-Infinity needs to be quoted for floating point values in postgresql

[kf8a]

It looks like postgres requires Nan and Infinity to be quoted when trying to insert them into a table. This is a tiny patch check for these values by overriding literal_float in the postgres adapter and adding the required quotes.

[jeremyevans]

I agree this should be fixed. However, your current patch will hurt performance, since it calls to_s on all Floats, and then does three string comparisons. For better performance, I would recommend something like:

if value.finite?
  super
elsif value > 0
  "'Infinity'"
elsif value < 0
  "'-Infinity'"
else
  "'NaN'"
end

Your specs should also check for correct results by actually inserting results in a table and reading the results back, not just checking that the expected SQL is produced.

If you can make those changes, I would appreciate it. If not, I'll try to take care of it myself before 3.33.0 is released.

[kf8a]

No problem, thanks for a great library.

I've modified the if statement as you suggested to reduce the work and added tests for the actual insertion and retrieval. I added conversions on the way out of the database in def float. I don't know if it's possible to reduce the comparisons on the way from the database. It might be possible to do something like:

def float(s)
    if s.to_f.to_s == s
       s.to_f
    else
      ...check for NaN and Infinity
    end
end

but that would be two type conversion plus one comparison vs 3 comparisons.

[jeremyevans]

I'll do some microbenchmarking to determine the fastest way. Otherwise, this looks good. I should be able to merge this later today. Thanks for the help!