Bug in blank attribute detection w/o column backing

[chrisarcand]

default_value_for/lib/default_value_for.rb

Lines 159 to 170 in c52d291

	attribute_blank = if attributes.has_key?(attribute)
	column = self.class.columns_hash[attribute]
	if column && column.type == :boolean
	attributes[attribute].nil?
	else
	attributes[attribute].blank?
	end
	elsif respond_to?(attribute)
	send(attribute).nil?
	else
	instance_variable_get("@#{attribute}").nil?
	end

The above code has a few more edge cases that are missed, specifically with the second two cases in the outer conditional where the attribute is not backed by a database column. The next two cases must account for the same issue (attribute can either be a boolean where false is not 'blank', it's a set value, but false.nil? == true, or a collection that is empty via blank?).

This whole thing should be cleaned up, with perhaps a few comments explaining each case.

See d155ba7#commitcomment-30274475

cc/ @romaind

[romaind]

@chrisarcand thanks a lot for taking what I mentionned into account.
I'll do some thinking and try to come up with a solution in the upcoming week

[romaind]

@chrisarcand currently working on that
it seems you've not tested the false.nil? case as replacing nil? with blank? line 167 doesn't break tests
I'll add that.
Or maybe you did, but weird that the tests don't break then