From: Daniel DeLorme <dan-ml@...42.com>
Date: 2006-07-31T00:57:26+09:00
Subject: Re: find_all wierdness

Oleg Kh wrote:
> My problem is as follows:
> 
> book.chapters.find_all{ |chapter| !chapter.pages.empty? }.size
> 
> Theoretically it should return a number of chapters that have pages in 
> them. However it doesn't do that at all. It simply returns a number of 
> all chapters.

Try to use select instead of find_all. In this case I think you are actually 
triggering ActiveRecord's find_all instead of the Enumerable#find_all that you 
were expecting. book.chapters is not an array but an association object. The 
ActiveRecord version is defined as:
   Project#milestones.find_all(conditions)
So in your case, you don't give any conditions as parameters and the method just 
ignores the block and returns all chapters. Sometimes Rails magic can bite you 
in the ass.

Daniel