Fix a bug where class extentions were conflicting with ActiveSupport

lib/couchrest/support/class.rb

@@ -25,151 +25,167 @@
 # 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
-  # Defines class-level and instance-level attribute reader.
+  module ClassExtension
-  #
+    def self.included(base)
-  # @param *syms<Array> Array of attributes to define reader for.
+      if CouchRest::ClassExtension::InstanceMethods.instance_methods.all? {|m| base.respond_to?(m)}
-  # @return <Array[#to_s]> List of attributes that were made into cattr_readers
+        # do nothing
-  #
+      elsif CouchRest::ClassExtension::InstanceMethods.instance_methods.any? {|m| base.respond_to?(m)}
-  # @api public
+        raise RuntimeError, "Conflicting extentions to Class, work it out"
-  #
+      else
-  # @todo Is this inconsistent in that it does not allow you to prevent
+        base.send(:include, CouchRest::ClassExtension::InstanceMethods)
-  # an instance_reader via :instance_reader => false
+      end
-  def cattr_reader(*syms)
+    end
-    syms.flatten.each do |sym|
+    
-      next if sym.is_a?(Hash)
+    module InstanceMethods
-      class_eval(<<-RUBY, __FILE__, __LINE__ + 1)
+      # Defines class-level and instance-level attribute reader.
-unless defined? @@#{sym}
+      #
-@@#{sym} = nil
+      # @param *syms<Array> Array of attributes to define reader for.
-end
+      # @return <Array[#to_s]> List of attributes that were made into cattr_readers
- 
+      #
-def self.#{sym}
+      # @api public
-@@#{sym}
+      #
-end
+      # @todo Is this inconsistent in that it does not allow you to prevent
- 
+      # an instance_reader via :instance_reader => false
-def #{sym}
+      def cattr_reader(*syms)
-@@#{sym}
+        syms.flatten.each do |sym|
-end
+          next if sym.is_a?(Hash)
-RUBY
+          class_eval(<<-RUBY, __FILE__, __LINE__ + 1)
+    unless defined? @@#{sym}
+    @@#{sym} = nil
     end
-  end
  
-  # Defines class-level (and optionally instance-level) attribute writer.
+    def self.#{sym}
-  #
+    @@#{sym}
-  # @param <Array[*#to_s, Hash{:instance_writer => Boolean}]> Array of attributes to define writer for.
+    end
-  # @option syms :instance_writer<Boolean> if true, instance-level attribute writer is defined.
-  # @return <Array[#to_s]> List of attributes that were made into cattr_writers
-  #
-  # @api public
-  def cattr_writer(*syms)
-    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
  
-def self.#{sym}=(obj)
+    def #{sym}
-@@#{sym} = obj
+    @@#{sym}
-end
+    end
-RUBY
+    RUBY
+        end
+      end
  
-      unless options[:instance_writer] == false
+      # Defines class-level (and optionally instance-level) attribute writer.
-        class_eval(<<-RUBY, __FILE__, __LINE__ + 1)
+      #
-def #{sym}=(obj)
+      # @param <Array[*#to_s, Hash{:instance_writer => Boolean}]> Array of attributes to define writer for.
-@@#{sym} = obj
+      # @option syms :instance_writer<Boolean> if true, instance-level attribute writer is defined.
-end
+      # @return <Array[#to_s]> List of attributes that were made into cattr_writers
-RUBY
+      #
+      # @api public
+      def cattr_writer(*syms)
+        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
+ 
+    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
+          end
+        end
+      end
+ 
+      # Defines class-level (and optionally instance-level) attribute accessor.
+      #
+      # @param *syms<Array[*#to_s, Hash{:instance_writer => Boolean}]> Array of attributes to define accessor for.
+      # @option syms :instance_writer<Boolean> if true, instance-level attribute writer is defined.
+      # @return <Array[#to_s]> List of attributes that were made into accessors
+      #
+      # @api public
+      def cattr_accessor(*syms)
+        cattr_reader(*syms)
+        cattr_writer(*syms)
+      end
+ 
+      # Defines class-level inheritable attribute reader. Attributes are available to subclasses,
+      # each subclass has a copy of parent's attribute.
+      #
+      # @param *syms<Array[#to_s]> Array of attributes to define inheritable reader for.
+      # @return <Array[#to_s]> Array of attributes converted into inheritable_readers.
+      #
+      # @api public
+      #
+      # @todo Do we want to block instance_reader via :instance_reader => false
+      # @todo It would be preferable that we do something with a Hash passed in
+      # (error out or do the same as other methods above) instead of silently
+      # moving on). In particular, this makes the return value of this function
+      # less useful.
+      def class_inheritable_reader(*ivars)
+        instance_reader = ivars.pop[:reader] if ivars.last.is_a?(Hash)
+ 
+        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
+          unless instance_reader == false
+            self.class_eval <<-RUBY, __FILE__, __LINE__ + 1
+    def #{ivar}
+    self.class.#{ivar}
+    end
+    RUBY
+          end
+        end
+      end
+ 
+      # Defines class-level inheritable attribute writer. Attributes are available to subclasses,
+      # each subclass has a copy of parent's attribute.
+      #
+      # @param *syms<Array[*#to_s, Hash{:instance_writer => Boolean}]> Array of attributes to
+      # define inheritable writer for.
+      # @option syms :instance_writer<Boolean> if true, instance-level inheritable attribute writer is defined.
+      # @return <Array[#to_s]> An Array of the attributes that were made into inheritable writers.
+      #
+      # @api public
+      #
+      # @todo We need a style for class_eval <<-HEREDOC. I'd like to make it
+      # class_eval(<<-RUBY, __FILE__, __LINE__), but we should codify it somewhere.
+      def class_inheritable_writer(*ivars)
+        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
+          unless instance_writer == false
+            self.class_eval <<-RUBY, __FILE__, __LINE__ + 1
+    def #{ivar}=(obj) self.class.#{ivar} = obj end
+    RUBY
+          end
+        end
+      end
+ 
+      # Defines class-level inheritable attribute accessor. Attributes are available to subclasses,
+      # each subclass has a copy of parent's attribute.
+      #
+      # @param *syms<Array[*#to_s, Hash{:instance_writer => Boolean}]> Array of attributes to
+      # define inheritable accessor for.
+      # @option syms :instance_writer<Boolean> if true, instance-level inheritable attribute writer is defined.
+      # @return <Array[#to_s]> An Array of attributes turned into inheritable accessors.
+      #
+      # @api public
+      def class_inheritable_accessor(*syms)
+        class_inheritable_reader(*syms)
+        class_inheritable_writer(*syms)
       end
     end
   end
- 
-  # Defines class-level (and optionally instance-level) attribute accessor.
-  #
-  # @param *syms<Array[*#to_s, Hash{:instance_writer => Boolean}]> Array of attributes to define accessor for.
-  # @option syms :instance_writer<Boolean> if true, instance-level attribute writer is defined.
-  # @return <Array[#to_s]> List of attributes that were made into accessors
-  #
-  # @api public
-  def cattr_accessor(*syms)
-    cattr_reader(*syms)
-    cattr_writer(*syms)
-  end
- 
-  # Defines class-level inheritable attribute reader. Attributes are available to subclasses,
-  # each subclass has a copy of parent's attribute.
-  #
-  # @param *syms<Array[#to_s]> Array of attributes to define inheritable reader for.
-  # @return <Array[#to_s]> Array of attributes converted into inheritable_readers.
-  #
-  # @api public
-  #
-  # @todo Do we want to block instance_reader via :instance_reader => false
-  # @todo It would be preferable that we do something with a Hash passed in
-  # (error out or do the same as other methods above) instead of silently
-  # moving on). In particular, this makes the return value of this function
-  # less useful.
-  def class_inheritable_reader(*ivars)
-    instance_reader = ivars.pop[:reader] if ivars.last.is_a?(Hash)
- 
-    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
+
-      unless instance_reader == false
+Class.send(:include, CouchRest::ClassExtension)
-        self.class_eval <<-RUBY, __FILE__, __LINE__ + 1
-def #{ivar}
-self.class.#{ivar}
-end
-RUBY
-      end
-    end
-  end
- 
-  # Defines class-level inheritable attribute writer. Attributes are available to subclasses,
-  # each subclass has a copy of parent's attribute.
-  #
-  # @param *syms<Array[*#to_s, Hash{:instance_writer => Boolean}]> Array of attributes to
-  # define inheritable writer for.
-  # @option syms :instance_writer<Boolean> if true, instance-level inheritable attribute writer is defined.
-  # @return <Array[#to_s]> An Array of the attributes that were made into inheritable writers.
-  #
-  # @api public
-  #
-  # @todo We need a style for class_eval <<-HEREDOC. I'd like to make it
-  # class_eval(<<-RUBY, __FILE__, __LINE__), but we should codify it somewhere.
-  def class_inheritable_writer(*ivars)
-    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
-      unless instance_writer == false
-        self.class_eval <<-RUBY, __FILE__, __LINE__ + 1
-def #{ivar}=(obj) self.class.#{ivar} = obj end
-RUBY
-      end
-    end
-  end
- 
-  # Defines class-level inheritable attribute accessor. Attributes are available to subclasses,
-  # each subclass has a copy of parent's attribute.
-  #
-  # @param *syms<Array[*#to_s, Hash{:instance_writer => Boolean}]> Array of attributes to
-  # define inheritable accessor for.
-  # @option syms :instance_writer<Boolean> if true, instance-level inheritable attribute writer is defined.
-  # @return <Array[#to_s]> An Array of attributes turned into inheritable accessors.
-  #
-  # @api public
-  def class_inheritable_accessor(*syms)
-    class_inheritable_reader(*syms)
-    class_inheritable_writer(*syms)
-  end
-end

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