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allow the :converter Proc form composed_of to return nil

This makes it possible to filter invalid input values before they are passed
into the value-object (like empty strings). This behaviour is only relevant
if the :allow_nil options is set to true. Otherwise you will get
the resulting NoMethodError.
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commit fa5f037551dfb860bf6359acf901915856646fea 1 parent 499825e
@senny senny authored
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15 activerecord/lib/active_record/aggregations.rb
@@ -187,7 +187,8 @@ module ClassMethods
# * <tt>:converter</tt> - A symbol specifying the name of a class method of <tt>:class_name</tt>
# or a Proc that is called when a new value is assigned to the value object. The converter is
# passed the single value that is used in the assignment and is only called if the new value is
- # not an instance of <tt>:class_name</tt>.
+ # not an instance of <tt>:class_name</tt>. If <tt>:allow_nil</tt> is set to true, the converter
+ # can return nil to skip the assignment.
#
# Option examples:
# composed_of :temperature, :mapping => %w(reading celsius)
@@ -234,16 +235,16 @@ def reader_method(name, class_name, mapping, allow_nil, constructor)
def writer_method(name, class_name, mapping, allow_nil, converter)
define_method("#{name}=") do |part|
+ unless part.is_a?(class_name.constantize) || converter.nil? || part.nil?
+ part = converter.respond_to?(:call) ?
+ converter.call(part) :
+ class_name.constantize.send(converter, part)
+ end
+
if part.nil? && allow_nil
mapping.each { |pair| self[pair.first] = nil }
@aggregation_cache[name] = nil
else
- unless part.is_a?(class_name.constantize) || converter.nil?
- part = converter.respond_to?(:call) ?
- converter.call(part) :
- class_name.constantize.send(converter, part)
- end
-
mapping.each { |pair| self[pair.first] = part.send(pair.last) }
@aggregation_cache[name] = part.freeze
end
View
18 activerecord/test/cases/aggregations_test.rb
@@ -109,6 +109,24 @@ def test_nil_assignment_results_in_nil
assert_nil customers(:david).gps_location
end
+ def test_nil_return_from_converter_is_respected_when_allow_nil_is_true
+ customers(:david).non_blank_gps_location = ""
+ customers(:david).save
+ customers(:david).reload
+ assert_nil customers(:david).non_blank_gps_location
+ end
+
+ def test_nil_return_from_converter_results_in_failure_when_allow_nil_is_false
+ assert_raises(NoMethodError) do
+ customers(:barney).gps_location = ""
+ end
+ end
+
+ def test_do_not_run_the_converter_when_nil_was_set
+ customers(:david).non_blank_gps_location = nil
+ assert_nil Customer.gps_conversion_was_run
+ end
+
def test_custom_constructor
assert_equal 'Barney GUMBLE', customers(:barney).fullname.to_s
assert_kind_of Fullname, customers(:barney).fullname
View
5 activerecord/test/models/customer.rb
@@ -1,7 +1,12 @@
class Customer < ActiveRecord::Base
+
+ cattr_accessor :gps_conversion_was_run
+
composed_of :address, :mapping => [ %w(address_street street), %w(address_city city), %w(address_country country) ], :allow_nil => true
composed_of :balance, :class_name => "Money", :mapping => %w(balance amount), :converter => Proc.new { |balance| balance.to_money }
composed_of :gps_location, :allow_nil => true
+ composed_of :non_blank_gps_location, :class_name => "GpsLocation", :allow_nil => true, :mapping => %w(gps_location gps_location),
+ :converter => lambda { |gps| self.gps_conversion_was_run = true; gps.blank? ? nil : GpsLocation.new(gps)}
composed_of :fullname, :mapping => %w(name to_s), :constructor => Proc.new { |name| Fullname.parse(name) }, :converter => :parse
end
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