Revert "Remove deprecated form_for with strings or symbols"

This code was not deprecated. What was deprecated is the following:

  form_for(:foo, @foo)

Which now should be rewritten as:

  form_for(@foo, :as => :foo)

The following format is valid:

  form_for(:foo)

This reverts commit be797750e6.

actionpack/lib/action_view/helpers/form_helper.rb

@@ -303,9 +303,15 @@ module ActionView
 
         options[:html] ||= {}
 
-        object      = record.is_a?(Array) ? record.last : record
-        object_name = options[:as] || ActiveModel::Naming.param_key(object)
-        apply_form_for_options!(record, options)
+        case record
+        when String, Symbol
+          object_name = record
+          object      = nil
+        else
+          object      = record.is_a?(Array) ? record.last : record
+          object_name = options[:as] || ActiveModel::Naming.param_key(object)
+          apply_form_for_options!(record, options)
+        end
 
         options[:html][:remote] = options.delete(:remote)
         builder = options[:parent_builder] = instantiate_builder(object_name, object, options, &proc)

actionpack/test/template/erb/form_for_test.rb

@@ -1,11 +1,10 @@
 require "abstract_unit"
 require "template/erb/helper"
-require "controller/fake_models"
 
 module ERBTest
   class TagHelperTest < BlockTestCase
     test "form_for works" do
-      output = render_content "form_for(Post.new, :url => {:controller => 'blah', :action => 'update'})", ""
+      output = render_content "form_for(:staticpage, :url => {:controller => 'blah', :action => 'update'})", ""
       assert_match %r{<form.*action="/blah/update".*method="post">.*</form>}, output
     end
   end

actionpack/test/template/erb/helper.rb

@@ -4,8 +4,6 @@ module ERBTest
     include ActionView::Helpers::TagHelper
     include ActionView::Helpers::JavaScriptHelper
     include ActionView::Helpers::FormHelper
-    include ActionView::Context
-    include ActionController::RecordIdentifier
 
     attr_accessor :output_buffer, :controller
 
@@ -22,4 +20,4 @@ module ERBTest
       "<%= #{str} do %>#{rest}<% end %>"
     end
   end
-end
+end

actionpack/test/template/form_helper_test.rb

@@ -781,6 +781,23 @@ class FormHelperTest < ActionView::TestCase
     assert_dom_equal expected, output_buffer
   end
 
+  def test_form_for_without_object
+    form_for(:post, :html => { :id => 'create-post' }) do |f|
+      concat f.text_field(:title)
+      concat f.text_area(:body)
+      concat f.check_box(:secret)
+    end
+
+    expected = whole_form("/", "create-post") do
+      "<input name='post[title]' size='30' type='text' id='post_title' value='Hello World' />" +
+      "<textarea name='post[body]' id='post_body' rows='20' cols='40'>Back to the hill and over it again!</textarea>" +
+      "<input name='post[secret]' type='hidden' value='0' />" +
+      "<input name='post[secret]' checked='checked' type='checkbox' id='post_secret' value='1' />"
+    end
+
+    assert_dom_equal expected, output_buffer
+  end
+
   def test_form_for_with_index
     form_for(@post, :as => "post[]") do |f|
       concat f.label(:title)
@@ -850,6 +867,22 @@ class FormHelperTest < ActionView::TestCase
     I18n.locale = old_locale
   end
 
+  def test_submit_without_object_and_locale_strings
+    old_locale, I18n.locale = I18n.locale, :submit
+
+    form_for(:post) do |f|
+      concat f.submit :class => "extra"
+    end
+
+    expected = whole_form do
+      "<input name='commit' class='extra' id='post_submit' type='submit' value='Save changes' />"
+    end
+
+    assert_dom_equal expected, output_buffer
+  ensure
+    I18n.locale = old_locale
+  end
+
   def test_submit_with_object_and_nested_lookup
     old_locale, I18n.locale = I18n.locale, :submit