bug 1108: fix a bug with find_or_create_by and additional values

There was a bug with find_or_create_by_x introduced in 2.3.9 - if you
included extra parameters for the create() then those parameters would
confuse the find() so you'd never get to the create().  This patch
filters the parameters so we only pass to find() the subset that it's
interested in.  The code for the filtering was modelled on the code in
base.rb's method_missing().

activerecord/lib/active_record/associations/association_collection.rb

@@ -381,7 +381,8 @@ def method_missing(method, *args)
             return find(:first, :conditions => args.first) || create(args.first)
           when /^find_or_create_by_(.*)$/
             rest = $1
-            return  send("find_by_#{rest}", *args) ||
+            find_args = pull_finder_args_from(DynamicFinderMatch.match(method).attribute_names, *args)
+            return  send("find_by_#{rest}", find_args) ||
                     method_missing("create_by_#{rest}", *args)
           when /^create_by_(.*)$/
             return create($1.split('_and_').zip(args).inject({}) { |h,kv| k,v=kv ; h[k] = v ; h })
@@ -448,6 +449,25 @@ def add_record_to_target_with_callbacks(record)
         end
 
       private
+        # Separate the "finder" args from the "create" args given to a
+        # find_or_create_by_ call.  Returns an array with the
+        # parameter values in the same order as the keys in the
+        # "names" array.  This code was based on code in base.rb's
+        # method_missing method.
+        def pull_finder_args_from(names, *args)
+          attributes = names.collect { |name| name.intern }
+          attribute_hash = {}
+          args.each_with_index do |arg, i|
+            if arg.is_a?(Hash)
+              attribute_hash.merge! arg
+            else
+              attribute_hash[attributes[i]] = arg
+            end
+          end
+          attribute_hash = attribute_hash.with_indifferent_access
+          attributes.collect { |attr| attribute_hash[attr] }
+        end
+
         def create_record(attrs)
           attrs.update(@reflection.options[:conditions]) if @reflection.options[:conditions].is_a?(Hash)
           ensure_owner_is_not_new

activerecord/test/cases/associations/has_many_associations_test.rb

@@ -65,6 +65,23 @@ def test_find_or_create_by
     assert_equal person, person.readers.first.person
   end
 
+  def test_find_or_create_by_with_additional_parameters
+    post = Post.create! :title => 'test_find_or_create_by_with_additional_parameters', :body => 'this is the body'
+    comment = post.comments.create! :body => 'test comment body', :type => 'test'
+
+    assert_equal comment, post.comments.find_or_create_by_body('test comment body')
+
+    post.comments.find_or_create_by_body(:body => 'other test comment body', :type => 'test')
+    assert_equal 2, post.comments.count
+    assert_equal 2, post.comments.length
+    post.comments.find_or_create_by_body('other other test comment body', :type => 'test')
+    assert_equal 3, post.comments.count
+    assert_equal 3, post.comments.length
+    post.comments.find_or_create_by_body_and_type('3rd test comment body', 'test')
+    assert_equal 4, post.comments.count
+    assert_equal 4, post.comments.length
+  end
+
   def test_find_or_create
     person = Person.create! :first_name => 'tenderlove'
     post   = Post.find :first