Fix a bug where class extentions were conflicting with ActiveSupport

lib/couchrest/support/class.rb

@@ -25,7 +25,19 @@
 # example, an array without those additions being shared with either their
 # parent, siblings, or children, which is unlike the regular class-level
 # attributes that are shared across the entire hierarchy.
-class Class
+module CouchRest
+  module ClassExtension
+    def self.included(base)
+      if CouchRest::ClassExtension::InstanceMethods.instance_methods.all? {|m| base.respond_to?(m)}
+        # do nothing
+      elsif CouchRest::ClassExtension::InstanceMethods.instance_methods.any? {|m| base.respond_to?(m)}
+        raise RuntimeError, "Conflicting extentions to Class, work it out"
+      else
+        base.send(:include, CouchRest::ClassExtension::InstanceMethods)
+      end
+    end
+    
+    module InstanceMethods
       # Defines class-level and instance-level attribute reader.
       #
       # @param *syms<Array> Array of attributes to define reader for.
@@ -39,18 +51,18 @@ class Class
         syms.flatten.each do |sym|
           next if sym.is_a?(Hash)
           class_eval(<<-RUBY, __FILE__, __LINE__ + 1)
-unless defined? @@#{sym}
-@@#{sym} = nil
-end
+    unless defined? @@#{sym}
+    @@#{sym} = nil
+    end
  
-def self.#{sym}
-@@#{sym}
-end
+    def self.#{sym}
+    @@#{sym}
+    end
  
-def #{sym}
-@@#{sym}
-end
-RUBY
+    def #{sym}
+    @@#{sym}
+    end
+    RUBY
         end
       end
  
@@ -65,21 +77,21 @@ RUBY
         options = syms.last.is_a?(Hash) ? syms.pop : {}
         syms.flatten.each do |sym|
           class_eval(<<-RUBY, __FILE__, __LINE__ + 1)
-unless defined? @@#{sym}
-@@#{sym} = nil
-end
+    unless defined? @@#{sym}
+    @@#{sym} = nil
+    end
  
-def self.#{sym}=(obj)
-@@#{sym} = obj
-end
-RUBY
+    def self.#{sym}=(obj)
+    @@#{sym} = obj
+    end
+    RUBY
  
           unless options[:instance_writer] == false
             class_eval(<<-RUBY, __FILE__, __LINE__ + 1)
-def #{sym}=(obj)
-@@#{sym} = obj
-end
-RUBY
+    def #{sym}=(obj)
+    @@#{sym} = obj
+    end
+    RUBY
           end
         end
       end
@@ -114,19 +126,19 @@ RUBY
  
         ivars.each do |ivar|
           self.class_eval <<-RUBY, __FILE__, __LINE__ + 1
-def self.#{ivar}
-return @#{ivar} if self.object_id == #{self.object_id} || defined?(@#{ivar})
-ivar = superclass.#{ivar}
-return nil if ivar.nil? && !#{self}.instance_variable_defined?("@#{ivar}")
-@#{ivar} = ivar && !ivar.is_a?(Module) && !ivar.is_a?(Numeric) && !ivar.is_a?(TrueClass) && !ivar.is_a?(FalseClass) && !ivar.is_a?(Symbol) ? ivar.dup : ivar
-end
-RUBY
+    def self.#{ivar}
+    return @#{ivar} if self.object_id == #{self.object_id} || defined?(@#{ivar})
+    ivar = superclass.#{ivar}
+    return nil if ivar.nil? && !#{self}.instance_variable_defined?("@#{ivar}")
+    @#{ivar} = ivar && !ivar.is_a?(Module) && !ivar.is_a?(Numeric) && !ivar.is_a?(TrueClass) && !ivar.is_a?(FalseClass) && !ivar.is_a?(Symbol) ? ivar.dup : ivar
+    end
+    RUBY
           unless instance_reader == false
             self.class_eval <<-RUBY, __FILE__, __LINE__ + 1
-def #{ivar}
-self.class.#{ivar}
-end
-RUBY
+    def #{ivar}
+    self.class.#{ivar}
+    end
+    RUBY
           end
         end
       end
@@ -147,14 +159,14 @@ RUBY
         instance_writer = ivars.pop[:instance_writer] if ivars.last.is_a?(Hash)
         ivars.each do |ivar|
           self.class_eval <<-RUBY, __FILE__, __LINE__ + 1
-def self.#{ivar}=(obj)
-@#{ivar} = obj
-end
-RUBY
+    def self.#{ivar}=(obj)
+    @#{ivar} = obj
+    end
+    RUBY
           unless instance_writer == false
             self.class_eval <<-RUBY, __FILE__, __LINE__ + 1
-def #{ivar}=(obj) self.class.#{ivar} = obj end
-RUBY
+    def #{ivar}=(obj) self.class.#{ivar} = obj end
+    RUBY
           end
         end
       end
@@ -172,4 +184,8 @@ RUBY
         class_inheritable_reader(*syms)
         class_inheritable_writer(*syms)
       end
+    end
+  end
 end
+
+Class.send(:include, CouchRest::ClassExtension)

spec/couchrest/support/class_spec.rb

@@ -0,0 +1,59 @@
+require File.join(File.dirname(__FILE__), '..', '..', 'spec_helper')
+require File.join(File.dirname(__FILE__), '..', '..', '..', 'lib', 'couchrest', 'support', 'class')
+
+describe CouchRest::ClassExtension do
+  
+  before :all do
+    class FullyDefinedClassExtensions
+      def self.respond_to?(method)
+        if CouchRest::ClassExtension::InstanceMethods.instance_methods.include?(method)
+          true
+        else
+          super
+        end
+      end
+    end
+    
+    class PartDefinedClassExtensions
+      def self.respond_to?(method)
+        methods = CouchRest::ClassExtension::InstanceMethods.instance_methods
+        methods.delete('cattr_reader')
+        
+        if methods.include?(method)
+          false
+        else
+          super
+        end
+      end
+    end
+    
+    class NoClassExtensions
+      def self.respond_to?(method)
+        if CouchRest::ClassExtension::InstanceMethods.instance_methods.include?(method)
+          false
+        else
+          super
+        end
+      end
+    end
+
+
+  end
+  
+  it "should not include InstanceMethods if the class extensions are already defined" do
+    FullyDefinedClassExtensions.send(:include, CouchRest::ClassExtension)
+    FullyDefinedClassExtensions.ancestors.should_not include(CouchRest::ClassExtension::InstanceMethods)
+  end
+  
+  it "should raise RuntimeError if the class extensions are only partially defined" do
+    lambda {
+      PartDefinedClassExtensions.send(:include, CouchRest::ClassExtension)
+    }.should raise_error(RuntimeError)
+  end
+  
+  it "should include class extensions if they are not already defined" do
+    NoClassExtensions.send(:include, CouchRest::ClassExtension)
+    NoClassExtensions.ancestors.should include(CouchRest::ClassExtension::InstanceMethods)
+  end
+  
+end