Fix :insert_mode => :button bug

Setting :insert_mode to :button was causing a crash. Here was the
issue:

This gem was monkey patching sectionOptions to return the Ruby
object's `options` instance variable. However, sectionOptions was
being called from the Obj-C section initializer
(XLFormSectionDescriptor.formSectionWithTitle) BEFORE we were able to
set `options` on the ruby object. So it was

Why was this only an issue with the :button option? Well:
In that Obj-C initializer there's a call to canInsertUsingButton:
- https://github.com/xmartlabs/XLForm/blob/master/XLForm/XL/Descriptors/XLFormSectionDescriptor.m#L85
- https://github.com/xmartlabs/XLForm/blob/master/XLForm/XL/Descriptors/XLFormSectionDescriptor.m#L322-L325

That method is a two-part conditional. The first is 'is the insert
mode set to button?' and the second is 'do the section options indicate that
I can insert'. The second part was where the crash was occurring but
it was never getting there because of the first part was evaluating to
false.

The main change here is to update our `sectionOptions` monkeypatch
to use the ruby instance variable options if set but otherwise
fallback to the initial value.

app/screens/test_form_screen.rb

@@ -174,6 +174,19 @@ def form_data
           }
         ]
       },
+      {
+        title: 'Multi-value with XLFormSectionInsertModeButton',
+        name: 'multi',
+        options: [:insert, :delete, :reorder],
+        insert_mode: :button,
+        cells: [
+          {
+            title: 'Some text',
+            name: :some_text,
+            type: :text
+          }
+        ]
+      },
       {
         title: 'Subcells',
         name: :sub_cells,

lib/ProMotion/XLForm/xl_form_patch.rb

@@ -60,17 +60,17 @@ def cellForFormController(form_controller)
       end
 
       if self.cell && self.cell.respond_to?(:setup)
-        self.cell.setup(cell_data, form_controller) 
+        self.cell.setup(cell_data, form_controller)
       end
       self.configureCellAtCreationTime
     end
-    
-    self.cell 
+
+    self.cell
   end
 end
 
 class XLFormSectionDescriptor
-  attr_accessor :section_data, :options
+  attr_accessor :section_data
 
   def self.section(section_data)
     title = section_data[:title]
@@ -81,21 +81,26 @@ def self.section(section_data)
 
     section = XLFormSectionDescriptor.formSectionWithTitle(title, sectionOptions: options, sectionInsertMode: insert_mode)
     section.section_data = section_data
-    section.options = options
+
     section
   end
 
   def options=(value)
-    @options = self.class.parse_section_options(value)
+    @section_options = self.class.parse_section_options(value)
   end
 
-  def options
-    @options
-  end
+  # Since `sectionOptions` is a property on the Objective-C class and not a
+  # Ruby method we can't use `super` to fallback when overriding the method.
+  # To achieve the same thing we create an alias and use that instead.
+  alias :originalSectionOptions :sectionOptions
 
+  # This property/method is used in the Objective-C initializer and is called
+  # before we ever have a chance to set @section_options so we need to be able
+  # to fallback to the original.
   def sectionOptions
-    options
+    @section_options || originalSectionOptions
   end
+  alias_method :options, :sectionOptions
 
   def self.parse_section_options(options)
     return section_options(:none) if options.nil?

lib/ProMotion/XLForm/xl_form_screen.rb

@@ -188,7 +188,7 @@ def enabled=(value)
     def enabled?
       !self.form.isDisabled
     end
-    
+
     # dismiss keyboard
     def dismiss_keyboard
       self.view.endEditing true
@@ -283,7 +283,7 @@ def tableView(table_view, heightForRowAtIndexPath: index_path)
       cell_class = cell.class
       if cell_class.respond_to?(:formDescriptorCellHeightForRowDescriptor)
         return cell_class.formDescriptorCellHeightForRowDescriptor(row)
-      elsif row.respond_to?(:cell_data) && row.cell_data[:height]
+      elsif row.respond_to?(:cell_data) && row.cell_data && row.cell_data[:height]
         return row.cell_data[:height]
       end
       self.tableView.rowHeight

spec/test_xlform_screen_spec.rb

@@ -17,8 +17,8 @@ def form_screen
     view("Some help text").should.not.be.nil
   end
 
-  it "contains 8 sections" do
-    views(UITableView).first.numberOfSections.should == 8
+  it "contains 9 sections" do
+    views(UITableView).first.numberOfSections.should == 9
   end
 
   it "contains 1 section with 8 fields" do