Serialize BigDecimals as Floats when using to_yaml. Closes #8746 [ernesto.jimenez]

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@8877 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

3 files changed, 34 insertions, 0 deletions

diff --git a/activesupport/CHANGELOG b/activesupport/CHANGELOG
index 334772d947..468285ec43 100644
--- a/activesupport/CHANGELOG
+++ b/activesupport/CHANGELOG
@@ -1,5 +1,7 @@
 *SVN*
 
+* Serialize BigDecimals as Floats when using to_yaml. #8746 [ernesto.jimenez]
+
 * Adding TimeWithZone #to_yaml, #to_datetime, #eql? and method aliases for duck-typing compatibility with Time [Geoff Buesing]
 
 * TimeWithZone #in_time_zone returns +self+ if zone argument is the same as #time_zone [Geoff Buesing]
diff --git a/activesupport/lib/active_support/core_ext/bigdecimal/conversions.rb b/activesupport/lib/active_support/core_ext/bigdecimal/conversions.rb
index dcdb08aea0..d2504302cd 100644
--- a/activesupport/lib/active_support/core_ext/bigdecimal/conversions.rb
+++ b/activesupport/lib/active_support/core_ext/bigdecimal/conversions.rb
@@ -1,6 +1,29 @@
+require 'yaml'
+
 class BigDecimal #:nodoc:
   alias :_original_to_s :to_s
   def to_s(format="F")
     _original_to_s(format)
   end
+
+  yaml_as "tag:yaml.org,2002:float"
+  def to_yaml( opts = {} )
+    YAML::quick_emit( nil, opts ) do |out|
+      # This emits the number without any scientific notation.
+      # I prefer it to using self.to_f.to_s, which would lose precision.
+      #
+      # Note that YAML allows that when reconsituting floats
+      # to native types, some precision may get lost.
+      # There is no full precision real YAML tag that I am aware of.
+      str = self.to_s
+      if str == "Infinity"
+        str = ".Inf"
+      elsif str == "-Infinity"
+        str = "-.Inf"
+      elsif str == "NaN"
+        str = ".NaN"
+      end
+      out.scalar( "tag:yaml.org,2002:float", str, :plain )
+    end
+  end
 end
diff --git a/activesupport/test/core_ext/bigdecimal.rb b/activesupport/test/core_ext/bigdecimal.rb
new file mode 100644
index 0000000000..0417a2bca0
--- /dev/null
+++ b/activesupport/test/core_ext/bigdecimal.rb
@@ -0,0 +1,9 @@
+require 'abstract_unit'
+
+class BigDecimalTest < Test::Unit::TestCase
+  def test_to_yaml
+    assert_equal("--- 100000.30020320320000000000000000000000000000001\n", BigDecimal.new('100000.30020320320000000000000000000000000000001').to_yaml)
+    assert_equal("--- .Inf\n", BigDecimal.new('Infinity').to_yaml)
+    assert_equal("--- .NaN\n", BigDecimal.new('NaN').to_yaml)
+  end
+end
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