Define dynamic finders as real methods after first usage. Close #9317

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@7510 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

3 files changed, 74 insertions, 28 deletions

diff --git a/activerecord/CHANGELOG b/activerecord/CHANGELOG
index 215a37d3dc..aae27a9b58 100644
--- a/activerecord/CHANGELOG
+++ b/activerecord/CHANGELOG
@@ -1,5 +1,7 @@
 *SVN*
 
+* Define dynamic finders as real methods after first usage. [bscofield]
+
 * Deprecation: remove deprecated threaded_connections methods. Use allow_concurrency instead.  [Jeremy Kemper]
 
 * Associations macros accept extension blocks alongside modules.  #9346 [Josh
diff --git a/activerecord/lib/active_record/base.rb b/activerecord/lib/active_record/base.rb
index dd0ba08de0..16afb3b789 100755
--- a/activerecord/lib/active_record/base.rb
+++ b/activerecord/lib/active_record/base.rb
@@ -1220,6 +1220,9 @@ module ActiveRecord #:nodoc:
         #
         # This also enables you to initialize a record if it is not found, such as find_or_initialize_by_amount(amount) 
         # or find_or_create_by_user_and_password(user, password).
+        #
+        # Each dynamic finder or initializer/creator is also defined in the class after it is first invoked, so that future
+        # attempts to use it do not run through method_missing.
         def method_missing(method_id, *arguments)
           if match = /^find_(all_by|by)_([_a-zA-Z]\w*)$/.match(method_id.to_s)
             finder = determine_finder(match)
@@ -1227,45 +1230,45 @@ module ActiveRecord #:nodoc:
             attribute_names = extract_attribute_names_from_match(match)
             super unless all_attributes_exists?(attribute_names)
 
-            attributes = construct_attributes_from_arguments(attribute_names, arguments)
-
-            case extra_options = arguments[attribute_names.size]
-              when nil
-                options = { :conditions => attributes }
+            self.class_eval %{
+              def self.#{method_id}(*args) 
+                options = args.last.is_a?(Hash) ? args.pop : {}
+                attributes = construct_attributes_from_arguments([:#{attribute_names.join(',:')}], args)
+                finder_options = { :conditions => attributes }
+                validate_find_options(options)
                 set_readonly_option!(options)
-                ActiveSupport::Deprecation.silence { send(finder, options) }
 
-              when Hash
-                finder_options = extra_options.merge(:conditions => attributes)
-                validate_find_options(finder_options)
-                set_readonly_option!(finder_options)
-
-                if extra_options[:conditions]
-                  with_scope(:find => { :conditions => extra_options[:conditions] }) do
-                    ActiveSupport::Deprecation.silence { send(finder, finder_options) }
+                if options[:conditions]
+                  with_scope(:find => finder_options) do
+                    ActiveSupport::Deprecation.silence { send(:#{finder}, options) }
                   end
                 else
-                  ActiveSupport::Deprecation.silence { send(finder, finder_options) }
+                  ActiveSupport::Deprecation.silence { send(:#{finder}, options.merge(finder_options)) }
                 end
-
-              else
-                raise ArgumentError, "Unrecognized arguments for #{method_id}: #{extra_options.inspect}"
-            end
+              end
+            }
+            send(method_id, *arguments)
           elsif match = /^find_or_(initialize|create)_by_([_a-zA-Z]\w*)$/.match(method_id.to_s)
             instantiator = determine_instantiator(match)
             attribute_names = extract_attribute_names_from_match(match)
             super unless all_attributes_exists?(attribute_names)
 
-            if arguments[0].is_a?(Hash)
-              attributes = arguments[0].with_indifferent_access
-              find_attributes = attributes.slice(*attribute_names)
-            else
-              find_attributes = attributes = construct_attributes_from_arguments(attribute_names, arguments)
-            end
-            options = { :conditions => find_attributes }
-            set_readonly_option!(options)
+            self.class_eval %{
+              def self.#{method_id}(*args) 
+                if args[0].is_a?(Hash)
+                  attributes = args[0].with_indifferent_access
+                  find_attributes = attributes.slice(*[:#{attribute_names.join(',:')}])
+                else
+                  find_attributes = attributes = construct_attributes_from_arguments([:#{attribute_names.join(',:')}], args)
+                end
+                
+                options = { :conditions => find_attributes }
+                set_readonly_option!(options)
 
-            find_initial(options) || send(instantiator, attributes)
+                find_initial(options) || send(:#{instantiator}, attributes)
+              end
+            }
+            send(method_id, *arguments)
           else
             super
           end
diff --git a/activerecord/test/finder_test.rb b/activerecord/test/finder_test.rb
index b5bc5ae7f3..53fa24194e 100644
--- a/activerecord/test/finder_test.rb
+++ b/activerecord/test/finder_test.rb
@@ -324,6 +324,21 @@ class FinderTest < Test::Unit::TestCase
     assert_equal topics(:first), Topic.find_by_title("The First Topic")
     assert_nil Topic.find_by_title("The First Topic!")
   end
+  
+  def test_find_by_one_attribute_caches_dynamic_finder
+    # ensure this test can run independently of order
+    class << Topic; self; end.send(:remove_method, :find_by_title) if Topic.respond_to?(:find_by_title)
+    assert !Topic.respond_to?(:find_by_title)
+    t = Topic.find_by_title("The First Topic")
+    assert Topic.respond_to?(:find_by_title)
+  end
+
+  def test_dynamic_finder_returns_same_results_after_caching
+    # ensure this test can run independently of order
+    class << Topic; self; end.send(:remove_method, :find_by_title) if Topic.respond_to?(:find_by_title)
+    t = Topic.find_by_title("The First Topic")
+    assert_equal t, Topic.find_by_title("The First Topic") # find_by_title has been cached
+  end
 
   def test_find_by_one_attribute_with_order_option
     assert_equal accounts(:signals37), Account.find_by_credit_limit(50, :order => 'id')
@@ -334,6 +349,21 @@ class FinderTest < Test::Unit::TestCase
     assert_equal accounts(:rails_core_account), Account.find_by_credit_limit(50, :conditions => ['firm_id = ?', 6])
   end
 
+  def test_dynamic_finder_on_one_attribute_with_conditions_caches_method
+    # ensure this test can run independently of order
+    class << Account; self; end.send(:remove_method, :find_by_credit_limit) if Account.respond_to?(:find_by_credit_limit)
+    assert !Account.respond_to?(:find_by_credit_limit)
+    a = Account.find_by_credit_limit(50, :conditions => ['firm_id = ?', 6])
+    assert Account.respond_to?(:find_by_credit_limit)
+  end
+
+  def test_dynamic_finder_on_one_attribute_with_conditions_returns_same_results_after_caching
+    # ensure this test can run independently of order
+    class << Account; self; end.send(:remove_method, :find_by_credit_limit) if Account.respond_to?(:find_by_credit_limit)
+    a = Account.find_by_credit_limit(50, :conditions => ['firm_id = ?', 6])
+    assert_equal a, Account.find_by_credit_limit(50, :conditions => ['firm_id = ?', 6]) # find_by_credit_limit has been cached
+  end
+
   def test_find_by_one_attribute_with_several_options
     assert_equal accounts(:unknown), Account.find_by_credit_limit(50, :order => 'id DESC', :conditions => ['id != ?', 3])
   end
@@ -440,6 +470,13 @@ class FinderTest < Test::Unit::TestCase
     assert sig38.new_record?
   end
 
+  def test_dynamic_find_or_initialize_from_one_attribute_caches_method
+    class << Company; self; end.send(:remove_method, :find_or_initialize_by_name) if Company.respond_to?(:find_or_initialize_by_name)    
+    assert !Company.respond_to?(:find_or_initialize_by_name)
+    sig38 = Company.find_or_initialize_by_name("38signals")
+    assert Company.respond_to?(:find_or_initialize_by_name)
+  end
+
   def test_find_or_initialize_from_two_attributes
     another = Topic.find_or_initialize_by_title_and_author_name("Another topic","John")
     assert_equal "Another topic", another.title
@@ -464,6 +501,10 @@ class FinderTest < Test::Unit::TestCase
     assert_raises(ArgumentError) { Topic.find :first, :conditions => '1 = 1', :join => "It should be `joins'" }
   end
 
+  def test_dynamic_finder_with_invalid_params
+    assert_raises(ArgumentError) { Topic.find_by_title 'No Title', :join => "It should be `joins'" }
+  end
+
   def test_find_all_with_limit
     first_five_developers = Developer.find :all, :order => 'id ASC', :limit =>  5
     assert_equal 5, first_five_developers.length