Rails: money gem converts all amounts to zero

Question

I\'m trying to use the money gem to handle currency in my app but I\'m running into a strange error. This is what I have in my \"record\" model:

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Answer 1

tl;dr: change :amount to :price or :anything_else.

I've concluded that :amount is a keyword used somewhere in the money gem, so using it in your application causes problems.

It's a stretch, but the author uses the word amount in the first line of the documentation to describe what it does.

"Provides a Money class which encapsulates all information about an certain amount of money, such as its value and its currency." http://money.rubyforge.org/

In my Rails 3.0 project I've got 3 very similar models that extend the money class: Labor, Part, and Payment.

Labor and Part work fine using the attribute :price, but I wanted to use :amount in my Payment model, because it sounded better when reading aloud or in my head.

The problem I experienced is that Payment would take valid form input, toss out the :amount, save 0 in the database, and throw an undefined method `round' for nil:NilClass error, upon viewing the record:

I'm pretty sure that 0 is a symptom of nil getting converted by my migration options (:null => false, default => 0). I ruled out the View by debugging with safari web inspector, and then the Controller by raising and inspecting each variable. This sort of problem in the Model doesn't make a lot of sense, so I figured it had to be money. Then, I found this thread, and put it all together.

After rolling back the migration, and changing all :amount references to :price, it works perfectly.

I know this thread is a few months old, but hopefully this will help someone else avoid this pitfall in the future.

In the meantime, I'll be sticking to :price.