Fix for ruby 1.9 const_defined? method

ruby 1.9 breaks backwards compatibility by usіng the wrong default value
for its newly introduced second argument. This patch implements a work
around, to make this gem work on both ruby 1.8 and 1.9.

1 files changed, 14 insertions, 4 deletions

diff --git a/lib/json/common.rb b/lib/json/common.rb
index 1ca53cb..f8ce2da 100644
--- a/lib/json/common.rb
+++ b/lib/json/common.rb
@@ -23,7 +23,7 @@ module JSON
     # Set the JSON parser class _parser_ to be used by JSON.
     def parser=(parser) # :nodoc:
       @parser = parser
-      remove_const :Parser if const_defined? :Parser
+      remove_const :Parser if JSON.const_defined_in?(self, :Parser)
       const_set :Parser, parser
     end
 
@@ -34,8 +34,8 @@ module JSON
     def deep_const_get(path) # :nodoc:
       path.to_s.split(/::/).inject(Object) do |p, c|
         case
-        when c.empty?             then p
-        when p.const_defined?(c)  then p.const_get(c)
+        when c.empty?                     then p
+        when JSON.const_defined_in?(p, c) then p.const_get(c)
         else
           begin
             p.const_missing(c)
@@ -350,7 +350,7 @@ module JSON
   end
 
   # Shortuct for iconv.
-  if String.method_defined?(:encode)
+  if ::String.method_defined?(:encode)
     def self.iconv(to, from, string)
       string.encode(to, from)
     end
@@ -360,6 +360,16 @@ module JSON
       Iconv.iconv(to, from, string).first
     end
   end
+
+  if ::Object.method(:const_defined?).arity == 1
+    def self.const_defined_in?(modul, constant)
+      modul.const_defined?(constant)
+    end
+  else
+    def self.const_defined_in?(modul, constant)
+      modul.const_defined?(constant, false)
+    end
+  end
 end
 
 module ::Kernel